Exercise and Physical Activity During Pregnancy

During the childbearing year, from conception through postpartum recovery, a woman's body undergoes extensive changes which frequently necessitate many adaptations. Physical and hormonal changes occur gradually throughout the 9 months of pregnancy, and these are reversed in a matter of weeks during postpartum recovery. Skeletal tissue, muscle and connective tissue, blood volume, cardiac output, body weight, and posture are affected.

As more pregnant women engage in demanding occupations, physical activities, and sports, the obstetricians and midwives who take care of them must become knowledgeable about the physical changes of pregnancy and the effects of exercise on the mother and fetus. Because prevention is the best approach to health care, understanding both the bodily stresses that may result from pregnancy changes and the means to prevent unnecessary problems enables health care to be instituted early in pregnancy and continued through the postpartum period.

The value and possible hazards of physical exercise and sports activities during pregnancy have been debated for years.¹ Early observers correlated an uneventful pregnancy and easy labor with physical activity. In Exodus, Biblical writers observed that Hebrew slave women had an easier time giving birth than their sedentary Egyptian mistresses,¹ and in 9 B.C., Plutarch urged Spartan women to harden their bodies with exercise to decrease the pain of childbearing.²

In Victorian times, pregnant women were encouraged to remain indoors and keep themselves “confined.”³ With more women in the workplace in the 1930s and their apparent ease of birthing, physicians once again advocated “strong body movements” for sedentary pregnant women.⁴

Based on her work in India in the 1930s, Vaughan instituted antenatal exercise classes in England. She wrote that “flexible hips and spine are conducive to ease of labor,” and women were encouraged to squat.³ Exercise classes taught by physiotherapists became popular in Great Britain and Sweden, where they were valued for their effects on back and abdominal muscles.^4,5,6,7

During the mid-1950s, despite the lack of scientific proof of benefits, “keep fit” exercises introduced by obstetric physiotherapist Helen Heardman in Britain⁸ were included with relaxation and breathing skills in Grantly Dick-Read's book on pain management for labor.⁹ In fact, Heardman's own book delineated an excellent program of prenatal exercises which form the basis of the best of many prenatal exercise programs today.⁸ The Lamaze method, popularized in the United States in 1959 by Marjory Karmel¹⁰ and Elisabeth Bing,¹¹ focused on both physical and psychological preparation for childbirth. From the mid-1970s through the 1990s, the emphasis on health and the public's renewed involvement in exercise caught the interest of the “pregnant population.” Numerous books on prenatal exercise, as well as videotapes and audio cassettes, flooded the market,^{12,13,14,15,16,17,18} and community centers, hospitals, health maintenance organizations (HMOs), and industries began to offer exercise classes for expectant women. Physicians and midwives must be aware that some of these book authors and some instructors of prenatal exercise classes lack adequate training and may not have sufficient knowledge of the physiologic changes of pregnancy nor of the cautions expectant women should follow while exercising. Many expectant women enroll in regular aerobics classes and try to keep up with the nonpregnant participants or instructor, often to their detriment.

Before enrolling in a pregnancy exercise class, it is recommended that the expectant woman be past her first trimester, be under medical supervision, and be warned of any medical reason that either precludes her from taking the classes or warrants limitations.¹⁹ As outlined by the American College of Obstetrics and Gynecology (ACOG),^20,21 these conditions include heart disease, toxemia, ruptured membranes, risk of premature labor, intrauterine growth retardation, poor weight gain, vaginal or uterine bleeding, anemia, hypertension, and fetal distress. Consultation with health care providers or some degree of caution is necessary for expectant women with respiratory conditions such as asthma^20,22 or orthopedic conditions such as back and hip pain or joint problems.^8,23,24,25 The qualifications of the instructor of the prenatal exercise program should include a medical background; a knowledge of obstetrics, muscle physiology, and kinesthesiology; and experience working with expectant mothers.^19,22,25,26 Physicians should make inquiries regarding the qualifications of instructors before signing approval notes for their patients to attend classes. Two-way communication between the obstetrician and prenatal exercise instructors should be instituted to ensure the safety of the patient.^19,20,22,24 There is as yet no scientific evidence of tangible results of physical preparation in pregnancy in the reduction of the length of labor; however, observers feel that effective abdominal expulsive efforts by the mother can shorten the second stage.^27,28 No reduction in uterine inertia or episiotomies (which are performed routinely in the United States) has been documented, but there has been a lower incidence of cesarean birth correlated with physical fitness.

No relation has been noted between physical fitness of the mother and the newborn's birth length, head circumference, or 1-minute Apgar score,⁶ but recent studies have found that strenuous maternal exercise in pregnancy may negatively affect the mother's weight gain and in some cases causes decreased weight in the newborn infant.^29,30

Birth is a normal, natural, physiologic process. Supporting the premise that pregnancy is a state of health, both physical and mental aspects of body image must be considered. With an increase in body weight and a protuberant abdomen, most women feel heavy, unattractive, and cumbersome; their movements seem clumsy, uncoordinated, and lacking in agility. The pregnant woman's body image may reach an all-time low; her posture sags, and she loses her self-esteem and confidence.^31,32 There is a strong relation between physical and mental health, and exercise is generally thought to have tremendous psychological value and boost self-esteem.^33,34,35

With a well-regulated, nonstrenuous exercise program instituted in the fourth month of pregnancy through the postpartum period, a pregnant woman is able to maintain good physical condition, to develop a sensible, healthy approach to exercise, to increase her comfort in pregnancy, to deliberately prepare for postpartum recovery, and to sustain the necessary muscular activity for the work of childbirth. Feelings of well-being and confidence that result from whole-body exercise on a regular basis enable her to approach childbirth with positive expectations.

Physical activity improves circulation, appetite, digestion, and elimination, all of which are affected during pregnancy and in turn are mirrored in the pregnant woman's mental attitude.^22,32,33 Regular exercise and nutrition are recognized as contributing to a healthy and more comfortable pregnancy.

Self-esteem is reduced immeasurably after childbirth, when the woman is upset by her “ruined figure and additional folds of flesh.” Exercise during pregnancy and reinstituted soon after delivery ensures quicker postpartum healing and recuperation, with renewal of positive body image and self-esteem. These feelings of well-being and additional energy allow the new mother to feel that she is doing something for herself and enable her to better face the responsibilities of parenting.^17,18,35

As humans evolved to an upright posture, several points of structural weakness were created in the human body. These are further accentuated during pregnancy; potential problem areas are the vertebral column, the abdominal muscles, and the pelvic floor.

The vertebral column in the normal state has curves to counteract the forces that gravity exerts on the upright posture. The curves of the spine include a concavity in the cervical area, convexity in the thoracic region, concavity in the lumbar vertebrae, and convexity in the sacrum. The line of gravity passes through the mastoid of the skull, the shoulder, and the hip and knee joints to just anterior to the lateral malleolus. The pelvis lies at an angle of 65 degrees to the lumbar spine, and the pelvic angle determines the prominence of the abdomen and buttocks (Fig. 1). In the nonpregnant state, connective tissue is responsible for the tensile strength of major fascial structures, ligaments, and joints and is able to withstand all extra physical effort.

There is evidence to suggest that changes in connective tissue due to the hormonal effects of increased progesterone and relaxin during pregnancy reduce support and permit increased mobility in structures to which muscles and tendons are attached.^17,18,24,36 Examples include softening of the cervix, mobility of the symphysis pubis, and relaxation of the joints of the pelvis and lower back, especially the sacroiliac joints. Because of these changes and greater joint mobility, there is less stability of the hip and knee joints, which often causing discomfort and loss of balance. For these reasons, jerky, bouncing movements, quick turns, and jogging, which can cause additional strain and pain, should be avoided.²²

Abdominal fascia loosens due to hormonal effects early in pregnancy (long before the uterus is large enough to account for enlargement of the abdomen), thus allowing for greater stretching of the abdominal muscles. Generally, there is contact between the 2 rectus abdominis muscles below the umbilicus and 2 cm between these muscles above the umbilicus. With widening of the linea alba in pregnancy, a diastasis can occur in 28% of pregnancies in the second trimester; its incidence peaks in third trimester and remains high in the immediate postpartum. The diastasis results in a bulge of the abdominal wall on increase in intraabdominal pressure and a separation of a distance of more than two finger-widths between the rectae.^18,23,27 To evaluate this condition, the patient lays with her knees bent while the physician or midwife places his or her fingers below the xiphoid across the linea alba. The patient raises her head and shoulders off table while the physician moves his or her fingers distally to determine how many fingers fit into the space between the 2 rectus abdominus muscle bellies.²⁷ If diastasis is present, the patient is advised to perform the “curl-up” exercise daily by tilting the pelvis posteriorly, supporting the rectae muscles on either side with her hands, and exhaling while lifting her head.^22,23

Together with the downward pull of the gluteal muscles, the upward pull of the abdominals maintains the correct alignment of the pelvis in relation to the vertebral column. If these muscles are well toned, they adequately support the enlarged uterus during pregnancy. More frequently, there is increased lumbar lordosis.

Because of joint changes, some physicians believe that impairment of coordination of the larger movements and an increase in reaction time are also evident in pregnancy. Therefore, many advise against activities in which safety depends on precise coordination and instant responses, such as skiing.^19,20

Increased body weight is directly related to postural changes in the thoracic and abdominal regions. With increase in weight during pregnancy (11.4–15.9 kg [25–35 lb] normally), the abdominal muscles are stretched, there is protuberance of the uterus anteriorly, and the line of gravity is shifted forward.

To maintain her balance, the woman stands farther back on her heels and increases the width of her base. This accentuates the lordosis in the lumbar spine, causing the pelvis to tilt at a more acute angle to the vertebral column (see Fig. 1). Structural changes, weight redistribution, and hormonal alteration of joint stability put additional strain on the sacroiliac and hip joints. The muscles of the lower back are shortened under the increased work load, resulting in frequent backache and fatigue. The extra effort required to balance causes hyperextension of the knees and weight on the inner borders of the feet, resulting in the “waddling” gait of pregnancy, foot strain, and additional fatigue.³⁵

Compensation for this altered body alignment occurs in the upper back and neck region, with kyphosis, or rounding, of the shoulders and forward protrusion of the head. The rounding of the shoulders is further compounded by the additional 0.7 kg (1.5 lb) of weight in the breasts in preparation for lactation. This results in shortening of the pectoral muscles, added tension in the shoulders, and stretching of the rhomboid muscles, producing complaints of pain in the upper back between the scapulae. The protruded position of the head further alters postural sense, which must be relearned.³⁸ Head position also impacts on the nerves emerging from the cervical spine and often results in traction on the median and ulnar nerves, which is experienced as numbness, tingling, and pain in the hands and arms.³⁶ Increased vascularity and fluid retention may also contribute to these symptoms.²⁴

With the encroaching uterus putting pressure on the diaphragm in the seventh to ninth months of pregnancy, many women experience shortness of breath. The poor postural alignment described previously further compresses the lungs from above, decreasing lung capacity.

Postural Correction

Poor posture and some shortening of the hip flexor muscle group secondary to anterior rotation of the pelvis with stretching of the abdominal muscles may account for the high prevalence of back pain in pregnancy.^{24,36,37,38,39} Approximately 50% of women complain of backache associated with pregnancy^40,41; 10% of activities of daily living are limited by severe low back pain, and 70% of Swedish women use sick leave because of pregnancy-related back pain. To alleviate the magnitude of the problem, researchers devised a proactive program of postural education and supervised exercise before, during, and after pregnancy, with reported results of less back pain and lower incidence of sick leave.⁴²

Re-education of the pregnant woman and correction of postural alignment alleviate many joint strains, reduce fatigue, and assist with walking and breathing difficulties. Information and re-education is included by childbirth educators in Lamaze childbirth preparation classes,²⁸ but these classes usually begin in last trimester; therefore, re-education should be explained by the physician or midwife to women during prenatal office visits early in the pregnancy, before problems arise.

Realignment is best done in front of a full-length mirror or with the aid of a partner. Body weight should be evenly distributed through the center of each foot and midway between left and right feet. Knees are slightly bent to overcome hyperextended knees. Abdominal muscles are gently contracted and the buttocks tucked under to correct the tilt of the pelvis. The sternum is projected forward, which will stretch the upper back, allowing the shoulder girdle to extend comfortably posteriorly. The head is repositioned by upward stretching of the neck; the chin is tucked in with the top of the head maintained parallel to the floor (Fig. 2).

Maternal cardiovascular changes during pregnancy represent an “overload” state whether the woman exercises or not. There is an increase in maternal blood volume of 30% to 50% (~2.25 L) to meet the needs of sustaining the growing fetus.⁴³ Resting heart rates in the nonpregnant woman range from 66 to 72 beats per minute, rising to 81 to 88 beats per minute during pregnancy. Cardiac output increases 2.5 times as a function of raised stroke volume and heart rate and results in part from hypertrophy of the left ventricle.^20,44,45 Cardiac output reaches a maximum at 28 weeks' gestation and remains elevated throughout the rest of the pregnancy.³⁷ The pregnant women's red blood cell level increases by 25% to 30% and plasma volume increases by 45%, which results in a physiologic anemia.

From early in the third trimester, the added pressure of the enlarged uterus may impede inferior vena cava flow, causing postural hypotension. Cardiac output may be enhanced if a left or right lateral tilt is maintained in the recumbent position. Uterine pressure on the vena cavae also cause gravitational stasis of blood in the legs. ACOG Guidelines for Physical Activity in Pregnancy first dictated “no lying in the recumbent position after the 4th month.”^2,21 Later, these guidelines were modified to suggest placing a pillow behind the right buttock when recumbent. Research has demonstrated that lying on the back in healthy pregnant women does not have deleterious effects on the fetus.⁴⁶

Venous blood must be returned to the heart against the force of gravity when the body is upright. The increased volume of the circulatory system and effects of progesterone often cause veins to become prominent and varicosed. For this reason, sitting with legs crossed at the knees should be discouraged during everyday life but especially during pregnancy.³⁵

As pregnancy progresses, many women experience edema in the legs and feet which is unrelated to toxemia or medical conditions. Likewise, slowed circulation and retained fluid result in patients awakening in the morning with swollen or tingling fingers and wrists. Flexion, extension, and circular movements of the feet and hands are easily learned and helpful for relief of edema.

Respiratory System

Owing to a 4-cm upward compression of the diaphragm by the growing uterus, there is a decrease in the vertical dimension of the thoracic cavity. With relaxation of the ligamentous attachments, there is a compensatory enlargement of the rib cage, with resultant increased vital capacity. Resting ventilation rates and tidal volume both increase, causing a physiologic hyperventilation. The brain's respiratory center has a reduced threshold to blood levels of carbon dioxide, causing an increase in respiratory rate. Increased oxygen consumption in advanced pregnancy and capillary engorgement throughout the respiratory tract cause nasal congestion, making nasal breathing difficult and frequently creating additional problems with breathlessness, with or without exercise.

Effect of Exercise on the Cardiopulmonary System

When pregnant women exercise, cardiovascular and respiratory response naturally increase. The maternal heart rate accelerates from 94 to 170 beats per minute in relation to the strenuousness of the exercise.²⁰ Guidelines from ACOG indicate keeping heart rates below 140 beats per minute during exercise or physical activity as a precaution, even though heart rate and blood pressure return to pre-exercise rates within 30 minutes.^20,22 Systolic blood pressure rises from 30 mm Hg to 40 mm Hg, whereas the diastolic blood pressure rises only 10 mm Hg with exercise. Expiratory ventilation increases during exercise in pregnancy.³⁷ This results in a beneficial 18% increase in aerobic capacity; in women who did not exercise during pregnancy, aerobic capacity decreased.⁴⁷ Several researchers suggest that there is a training effect from participating in an ongoing exercise program and that exercise may help to maintain work efficiency at prepregnancy levels despite the demands of the pregnancy.^{34,35,36,37,38}

Effect of Exercise on the Fetus

Concerns about the effects of exercise on the uterine environment and the fetus have been voiced by many physicians. In particular, studies centered around the shift of blood from the splanchnic area to the skeletal muscles of pregnant women after a bout of exercise and the possible effects of this on the fetus.^33,48 Fears were dispelled by tests that showed that there was not only rapid reversal but a compensatory “flush-back,” with an increase in uterine blood flow after cessation of exercise.⁴⁰ Monitoring of the fetal heart in response to maternal exercise showed rates within normal limits and return to baseline within 30 minutes.^43,49,50,51

Studies on maternal exercise and birth outcome indicate that most fetuses are able to tolerate moderate maternal exercise programs that women continue throughout the pregnancy.^48,52,53 Research in recreational runners, aerobic dancers, and nonexercisers determined the incidence of spontaneous loss of pregnancy in all 3 groups combined was 19% (15% in the overall population). However, loss percentage by group was runners, 17%; dancers, 18%; and nonexercisers, 25%. Exercising does not alter pregnancy outcome or increase probability of spontaneous pregnancy loss.^48,50,53 Studies of endurance exercises (i.e. running and aerobics) over the course of pregnancy monitored exercisers every 6 to 8 weeks. Before the end of the first trimester, one third of study subjects stopped intensive exercising, forming two new groups (i.e. exercisers and nonexercisers). In each group, 9% experienced preterm labor before 37 weeks. Exercisers started labor 5 days earlier than nonexercisers and had lower incidences of obstetrical interventions, need for labor stimulation, episiotomy, cesarean birth, and epidural anesthesia as well as a shorter active stage of labor.^46,53,54

Decreases in birth weight and less maternal weight gain have been noted in women who continued high-performance activities during pregnancy.^32,34 Other studies contradict these findings of low birth weight, finding instead a higher rate of fetal anomalies, which could be related to hyperthermia experienced during intense exercise in early pregnancy.^48,55

Thermoregulatory System in Pregnancy

Basal metabolic rate (BMR), increases during pregnancy, and necessitates a 300-kcal increase in the pregnant woman's caloric intake. The physiologic changes and increase in adipose tissue insulation makes pregnant women feel warmer even at rest.^51,56,57 Research studies on maternal thermoregulation suggest that hyperthermia, specifically in the first trimester, can produce adverse effects on fetal development.⁴⁵ As maternal temperatures increase, so does the fetal temperature. Teratogenic effects of heat on the fetus have been demonstrated in animal research.

When exercising, pregnant women must be reminded to wear loose-fitting clothing and drink fluids before, during, and after exercise.⁴⁸ Women who are fit tend to maintain a cooler temperature because of their more efficient cardiovascular system.⁴⁶ Avoiding hyperthermia is one of the primary rationales for both the American College of Obstetricians and Gynecologists (ACOG) and American College of Sports Medicine (ASSM) in establishing safety guidelines for prenatal exercise intensity and duration.

A regimen of regulated exercises, done slowly and deliberately and without strain or to the point of fatigue, includes all areas of the body and assists with the postural correction described previously. These exercises improve tone and elasticity of slackened or stretched muscles (abdominals, rhomboids, upper back and neck muscles); stretch shortened muscles (lower back and pectorals); reduce tension in joints of the pelvis, shoulders, hips, and knees; support breasts by strengthening pectorals; and improve posture and increase vital capacity of the lungs. Although in many childbirth preparation classes a variety of exercises are taught,^{13,17,18,19,57,58} the following basic examples can be easily explained by the physician or midwife at the prenatal visits.

Guidelines for Exercise During Pregnancy/Postpartum

1. Regular exercise (3 times/week) is preferable to intermittent activity.²⁰
   
2. All exercises are done slowly and deliberately. Jerking or bouncing movements that strain joints should be avoided. Wooden or securely carpeted surfaces will reduce body shock and provide sure footing.
   
3. Activities requiring jumping, jarring motions or rapid change of direction should be avoided because of joint instability, and competitive activities and contact sports should be discouraged
   
4. Vigorous exercise should be avoided in very hot, humid weather (unless in an air-conditioned environment) and during periods of febrile illness.
   
5. It is vitally important to begin any exercise session with a period of warm-up exercises such as arm circling, shoulder and neck rotations, trunk flexion, and gentle knee bends.⁵⁷ This should be followed by stretching of the various muscle groups in the arms, legs, and trunk to prevent damage of muscle fibers and joint strain; these may include gentle yoga stretches¹⁷ that are not taken to the point of maximum resistance.²⁰
   
6. Similarly, each session ends with muscle and joint stretches⁵⁸ done slowly, without bouncing or jerky movements. “Cooling down” should be accompanied by slow and comfortable breathing and followed by a relaxation period.
   
7. Heart rate should be measured before the exercise session and at time of peak activity, and the target level of 140 beats per minute should not be exceeded except in strong athletes who have consulted and established their own target rates with their physicians.
   
8. Strenuous exercise should not exceed 15 minutes in duration, and exercises that employ or produce the Valsalva maneuver should be avoided.
   
9. Caloric intake should be adequate to meet the extra energy needs of pregnancy and lactation as well as the exercise performed. Liquids should be imbibed liberally before, during, and after exercise to prevent dehydration.
   
10. Maternal core temperature should not exceed 38.5°C.^48,54
    

Each patient progresses at her own rate, starting by doing each exercise for three or four repetitions and slowly building up to ten repetitions. Some exercises include specific breathing techniques in conjunction with the required movement (e.g. pelvic tilt with exhalation and release with inhalation; inhalation with two-arm stretching to the sides to expand the chest and exhalation with return to midline). Holding the breath on exertion of any exercise is not helpful; continuous breathing is to be encouraged. No exercise must be performed to the point of fatigue; rest and relaxation should be interspersed during the session.^37,57 Adding music to the exercise session enhances enjoyment and encourages rhythmic movements. At no time should the the toes pointed, because this often predisposes to calf cramps. Sit-ups or double leg raises should not be done during pregnancy nor attempted until after the 6-week postpartum checkup, because they put too much strain on the abdominals and encourage diastasis.^18,27,57 Positions that increase lumbar lor-dosis should be avoided to reduce possibility of backache.⁵⁹

Patients used to be discouraged from lying flat on her back for extended periods of time to minimize the possibility of slowing circulation to the uterus and prevent supine hypotension. However, there is no harm in lying recumbent for short periods while doing exercises,²⁰ and newest research^46,55 shows that in healthy pregnancies, it is not necessary for the patient to “never lie on her back after the fourth month,” as formerly advocated by ACOG.²¹ There are some exercises (e.g. abdominal curls) that are most effectively done while lying on the back, and the patient can change to alternate positions after each set. Exercises that increase circulation in and around the pelvis should be encouraged (e.g. pelvic tilt, abdominal exercises). Standing or side-lying positions can be substituted for executing hip and leg movements normally performed while recumbent.

Time should be set aside each day for some exercise and, where feasible, exercise should be incorporated into daily activities. ACOG guidelines suggest exercising 3 times per week.^1,21

Breathing Exercises

Because of the difficulties pregnant women may have with respiration during the second and third trimesters and the tendency to hold the breath during exercising, deliberate attention to continuous breathing is encouraged. This ensures a steady intake of oxygen as well as prepares the woman for the need to maintain uniform and rhythmic breathing during labor. Focused and relaxed abdominal and low chest breathing skills improve ventilation and enhance relaxation during pregnancy, through labor, and postpartum.¹¹

Pelvic Tilt

The pelvic tilt movement, which is slight, strengthens and tones the abdominal muscles and stretches the lower back muscles. It is most helpful for decreasing the lumbar lordosis, realigning posture, and reducing low back pain.

The patient lies on her back with both knees bent and feet on the floor or examination table about 45 cm (18 inches) apart. She breathes in through her nose, and as she breathes out through her relaxed mouth she presses the small of her back against the floor and notices the upward tilting movement of her pelvis and tightening in the abdominals. To make sure she is doing this exercise correctly, the physician can place her or his hand under the lumbar vertebrae and tell the patient to press down onto the hand. The woman holds this position for a count of four and then slowly releases as she inhales and exhales (Fig. 3). Once mastered, this exercise can be done while sitting, standing, or on all fours, with care being taken not to let the spine sag (Fig. 4). When doing the pelvic tilt in the standing position, slight bending of the knees will ensure that the movement is performed in the pelvic region and does not strain the hips. The pelvic tilt is particularly helpful for backache during pregnancy, labor, and the postpartum period^23,38,59 and is also useful as an abdominal toner.

Abdominal Toners

Abdominal toners are progressions of the pelvic tilt exercise and are excellent for toning and strengthening the rectus, or straight, abdominals and the oblique abdominals. These muscles are used in second-stage pushing and for postpartum curl-ups and waistline recovery.

RECTUS OR STRAIGHT ABDOMINALS.

The position is the same as for the pelvic tilt. A pillow placed under the head reduces pressure on vena cava. With inhalation, the patient relaxes. As she exhales, she tilts her pelvis as in the previous exercise, and then lifts her head and slowly stretches both arms toward her knees and holds this position for a count of four while breathing normally; she then relaxes to the starting position (Fig. 5). If a diastasis is diagnosed (i.e. if two fingers can be inserted between the recti), instead of stretching her arms forward the patient should brace her abdomen by placing both hands across it, holding on to the opposite sides of the muscle bellies.¹⁸

OBLIQUE ABDOMINALS.

The position is the same as described previously. Again, the patient begins with the pelvic tilt, but this time she lifts her head and both arms and stretches toward the left knee and holds this position for a count of four while breathing normally; she then relaxes slowly to the starting position.

The patient inhales and exhales a few times. With the next inhalation, she relaxes, and on exhalation repeats the pelvic tilt, this time bringing both arms to the right knee (see Fig. 5).

Hip, Knee, and Ankle

The starting positions for these exercises are either side-lying or standing. The body remains relaxed as the patient inhales (Fig. 6A). If patient is lying on her side, both knees are bent. As she exhales, she bends her knee toward her chest (Fig. 6B). While inhaling, she stretches her right leg forward by extending her knee and dorsiflexing her foot (Fig. 6C). With exhalation, she brings the straight leg back to midline (Fig. 6D), and with inhalation brings it back to the flexed starting position. This exercise is then repeated with the left leg while keeping the right leg flexed after the patient turns to lie on opposite side.

Neck and Shoulder Muscles

The exercise for the neck and shoulder muscles is done in the tailor sitting position (i.e. sitting like a tailor with knees flexed) or standing¹⁷ (Fig. 7). The patient drops her head forward and gently circles it to the left, upward, to the right, and forward in as large an arc as possible. This is done slowly and deliberately and is repeated on alternating sides, while being careful not to place pressure on the cervical vertebrae

The shoulders are raised toward the ears, pulled backward, and slowly circled down and forward. This exercise should be repeated several times; it can also be done with the woman's fingertips on her shoulders while lifting and circling the elbows forward, upward, and backward. Care must be taken to keep the back straight and to keep the chin from poking forward. These exercises are helpful in releasing tension in the neck and shoulder muscles and should be followed by postural alignment of the head, neck, and shoulders.

Upper Back and Abdominal Side Flexors

With the patient in the tailor sitting position or standing with legs apart for balance, the arms are bent at the sides, and the fingertips are placed on the shoulders. The right arm is stretched upward as the woman inhales (Fig. 8). Keeping the torso erect, the patient stretches her rib cage and upper back and then slowly lowers her arm to the starting position while exhaling. This is repeated with the left arm and then with both arms at once. The patient should progress to stretching her right arm and bending to the left while keeping her torso in alignment; the patient should then repeat this exercise by stretching her left arm and slowly bending to the right (Fig. 9). These exercises allow for greater vital capacity by stretching the rib cage and upper back and strengthening the abdominal side flexors in preparation for postpartum recovery. When the patient's posture demonstrates kyphosis, the pectorals are usually shortened; these stretching exercises are most beneficial in correction of this problem.

Breast Support

In the second and third trimesters, when breasts enlarge and increase in weight, as well as during the postpartum period, additional support of the breasts is necessary. Strengthening of the pectoral muscles, which support the breasts, is achieved through use of an easy exercise.

In the sitting position, the patient puts her hands together, as in prayer, with her elbows flexed at shoulder level. She slowly presses her hands together (Fig. 10). The position is held to a count of four and slowly released, and the exercise is repeated several times. Normal, regular breathing should accompany this exercise.

Adductors and Hamstrings

At one time it was thought that pregnant women should become accustomed to stretching of the adductors and internal rotators of the thighs for added comfort in expulsion. It was argued that use of stirrups for delivery put strain on these muscles as well as the hip and pelvic joints, and that with conscientious practice of some stretching exercises, the associated discomfort could be decreased.

Incorrect teaching or learning of the exercise could lead to subluxation of the pubic symphysis as a result of too-vigorous pressure on the knees or a bouncing movement, which initiates the stretch reflex, causing a rebound with further shortening and protective splinting of the muscles.¹⁸ The following exercise not only allows for some stretch of the adductors but, more importantly, allows for stretch of the tight hamstrings and low back extensors.^17,18,57,60 The patient sits on the floor with her legs extended and separated as widely as comfortable and her hands stretched forward with her arms kept at shoulder level. Gently and slowly, she flexes forward from the hips, maintaining her arms parallel to the floor while stretching them forward, not toward her toes (Fig. 11).At first this movement may feel uncomfortable, but with practice the discomfort eases. No jerking or bouncing movements should be done, only stretching forward slowly, holding for the count of four, and slowly releasing to the starting position.⁵⁷

Exercises Aiding Circulation

As discussed in the section on cardiovascular and respiratory changes, pressure from the enlarged uterus, dependency edema, dilated blood vessels, and blood stasis cause swelling in the lower extremities, fingers, and hands. Exercises to reduce swelling and improve blood circulation decrease patient discomfort and fatigue. To increase circulation in the legs and reduce edema of the feet, alternate flexion and extension of the ankles causes pumping action of the calf muscles that promotes the flow of blood (Fig. 12). These exercises should be repeated six to eight times and done slowly. Pointing of the toes and extreme plantar flexion may result in leg cramps and therefore should be avoided. Rotation of the ankles in wide circles, first in one direction and then the other, is another excellent exercise (see Fig. 12). The effects of this exercise on circulation can be enhanced if the legs are supported and raised higher than the hips so that gravity assists in return blood flow.

For swollen fingers and wrists, the patient should sit with her elbows flexed and supported on a table and her hands in the air. Alternate flexion and extension of the fist or rotation at the wrists, with gravity's assistance, reduces swelling and the associated tingling sensation.

Postpartum, the risk of thrombophlebitis is increased when patients have undergone cesarean birth under regional anesthesia with lengthy pressure on the calf muscles. Foot and ankle exercises in the recovery room and early ambulation improve circulation and prevent stasis.

Pelvic Floor

The importance of the pelvic floor (i.e. pubococcygeus or levator ani muscles) has been sadly neglected by obstetricians. These several-layered muscles, both voluntary and involuntary, form a figure-eight as they are slung in loops around the vaginal and urethral sphincters anteriorly and the anus posteriorly. They form the essential support of the pelvic organs, and their tone and elasticity are vital during everyday life, pregnancy, and childbirth, especially during second stage when the pelvic floor muscles must be consciously released to facilitate delivery. These muscles must then be rehabilitated immediately after the delivery or repair of the episiotomy, if performed, and consistently during the postpartum period if this pelvic organ support is to be maintained.

Sphincter control of the bladder and rectum is a vital function provided by the pelvic floor muscles. Women can be taught by their obstetricians/midwives to release these muscles voluntarily during pelvic examinations and during delivery of the infant's head so as to facilitate its expulsion. Teaching these exercises in prenatal exercise classes, childbirth education classes, or any exercise classes for all women of all ages is mandatory and cannot be emphasized enough.

Exercise of the pelvic floor, or Kegel's muscles, when frequently and conscientiously practiced, maintains tone in these muscles, reduces the possibility of urinary incontinence or difficulty with postpartum urination, and helps prevent prolapse of the uterus.⁶¹ Another important function of the pelvic floor muscles is their active contraction to enhance enjoyment during coital activity and reflex contraction during orgasm.^62,63

Kegel exercises entail gaining awareness of the muscles of the pelvic floor and learning how to consciously contract and release them. The patient is taught to stop and start the flow of urine midstream during urination by using the sphincters, gently yet firmly, several times; this exercise makes her aware of the action of these muscles. Once awareness has been gained, frequent practice is necessary to maintain muscle tone not associated with urine flow. For the first week, at least 6 repetitions should be done slowly, maintaining the tension for at least 5 seconds each time followed by release. Additional sets of contractions are added to build up to at least 5 sets of 6 repetitions each day.

Another effective exercise is to imagine that this hammock of muscles is an elevator on the first floor that successively rises in a smooth, controlled, progressively tighter fashion to the second, third, fourth, and fifth floors, holding at each floor and then, just as smoothly, releasing tension as the elevator descends to the fourth, third, second, and first floors.^22,35,57 The act of releasing and then “pushing into the basement” prepares the patient for the release and bulging of the perineum necessary for expulsion.⁵⁷

Postpartum exercise of these muscles should be instituted soon after delivery. Conscious effort should be directed to the contraction rather than to the release of these muscles. These exercises are included in preparation classes but can be taught by the physician at a prenatal visit, by the nurse in the delivery room, and again during the postpartum period.

With early exercising of the pelvic floor, postpartum swelling is reduced, which in turn reduces discomfort. Frequent contraction of these muscles enhances circulation, promotes healing of the episiotomy, and strengthens muscle tone. Incidence and severity of postpartum urinary incontinence can be reduced by early initiation and frequent practice of these exercises.

As with all these exercises, contraction is done slowly and with concentrated effort to facilitate toning of the muscles and to increase pelvic organ support by tensing successively harder, holding for 5 to 6 seconds, and releasing. Sets of six repetitions should be performed, and the number of sets should be gradually increased. During muscle contraction, the edges of the incision are pulled together rather than apart, and, with this reassurance, frequent practice must be encouraged. Daily exercise of these muscles, together with practice of the pelvic tilt, relieves the low, achy feeling experienced by many women during the postpartum period.⁶³

For many years, obstetricians recommended abstinence from intercourse during the last 6 weeks of pregnancy and for 6 weeks postpartum. Unless sexual activity is contraindicated for a specific medical reason, such as toxemia, multiple birth, threatened abortion, uterine bleeding, partner with venereal disease, incompetent cervix, or habitual aborter following orgasm, most physicians are now more liberal in their thinking, demonstrating understanding of the needs and desires of the expectant couple. Resolution of anxieties and “old wives' tales,” reassurance about absence of dangers, and ideas for experimentation with new positions should be the focus of the discussion with the patient.

Patients who have learned to contract the pelvic floor muscles can use this movement during intercourse. Contraction of these muscles during coitus constricts the vaginal canal and allows greater contact with the penis or fingers, thereby enhancing sexual stimulation for both partners. Practice during coitus also affords feedback by the sexual partner on the quality and strength of muscle contraction.

When some form of “usual” sexual activity is prohibited, it is crucial for the physician or midwife to explain to the patient and her partner the reasons for abstinence; to reassess the prohibition after a period of time, and to encourage them to explore other forms of sexual play.^31,61,62,63 Couples should be encouraged to discuss their feelings about the change in their sexual behaviors and to choose appropriate options for themselves. This will reduce the feelings of guilt and fear on the part of the woman and of sexual rejection on the part of her partner.³¹ There is no conclusive evidence that coitus and orgasm are harmful to those pregnancies without predisposing factors such as bacteriuria, hypertension, placenta previa, partner's venereal disease, conditions necessitating bed rest, or habitual abortion. In several studies, coitus could not be implicated as the cause for premature labor, rupture of membranes, bleeding, or infection.⁶³ Poor research methodologic factors hinder the acceptance of the reports that intercourse is among the factors that increase the risk of prenatal hemorrhage.⁶³

Physicians should make their patients aware of some exercises that put strain on the pregnant body and frequently lead to increased discomfort or problems post partum. Due to the continuing paucity of definitive guidelines from research, recommendations for physical activity continue to rely of the pregnant women's perception of comfort and common sense.^22,57,64

The following are exercises that require restrictions.

1. Any exercise that increases the lumbar lordosis; puts strain on the sacroiliac joints, hips, or knees; or overtaxes the abdominal muscles. This includes some yoga positions advocated in numerous books available for expectant patients and included in some prenatal exercise classes.
   
2. Two-leg raises from the recumbent position or full sit-ups from the recumbent position (see Abdominal Toners).
   
3. Bridging, or lifting the buttocks off the floor from the recumbent position, if it cannot be done without increasing the lordosis.
   
4. Any exercise that encourages bouncing, bobbing, or jerking movements, as found in many aerobics or jazzercise classes popular today. Many of jazz-boxing class movements are excellent but, as with activities from step class routines, they need to be slowed down to ensure proper breathing and ensure maintenance of balance.
   
5. Deep knee squats for women unaccustomed to this position to prevent strain on knee and ankle ligaments. Women can be encouraged to slowly bend theirknees from the standing position to attain an eventual squatting position while leaning upright against a wall for balance; this exercise is excellent for delivery.
   
6. Hyperextension of knees in standing position puts strain on the knees. Knees can be held in a gentle bend, which will help attain pelvic tilt and alleviate backache.
   
7. Exercises that involve pointing the toes and plantar flexion of the feet can cause calf cramps.
   
8. Exercises done past point of fatigue, that create pain, or that induce hyperthermia should not be performed by the pregnant woman.
   

Expectant mothers must respect signals from their body and stop exercising if there is pain and to rest when fatigued. They must take extra precautions when exercising during hot and humid weather. They must maintain water intake, stop frequently to rest, eat adequately before exercise, rest afterward, be aware of fetal activity, and consult the physician if uterine contractions become regular. Likewise, they must stop exercising if they experience shortness of breath, dizziness, or faintness.

In everyday living, many people do not use good body mechanics and as a result put strain on muscles, ligaments, and joints while performing daily chores. In pregnancy, this strain is increased, whether sitting, standing, or walking (Fig. 13), and the patient frequently needs re-education to maintain body alignment without undue strain or pressure.

The following exercises can be easily shown to the patient by her physician. In particular, the first one can be demonstrated to the patient when she comes for her prenatal visits. In changing from sitting on the examining table to a lying position, many women lie straight back, putting severe strain on the abdominal muscles and joints of the back. The office nurse or physician can correct this by telling the patient to bend her knees, roll to one side, lower her body using her arms, and then roll to her back (Fig. 14).

Changing from lying to sitting positions is frequently done incorrectly by “jackknifing up,” which strains the already stretched abdominal muscles, causes further separation of the recti, and results in backache. The change should be made slowly to avoid dizziness. Again, the patient bends her knees, rolls to one side, and raises her body by pushing up on her hands.

To pick up objects from the floor, the patient should squat by bending her knees while keeping her back straight and then lift the object by straightening the knees rather than bending from the waist; this method reduces back strain, tones the muscles of the thighs, and affords better weight distribution (Fig. 15). While climbing stairs and doing household chores, the patient should use her legs as much as possible and avoid flexion of the back.

Just as important as exercises to tone and maintain the body in optimal condition, is the need for rest and relaxation during the pregnancy.^17,57,60 Cardiac and basal metabolism are accelerated, the expectant mother's weight has increased, and fatigue becomes a problem, especially in the last trimester. Patients need to be encouraged to take breaks during their daily work, put their feet up, and replenish their energy by consciously releasing muscular tension in the body.

This can be done in any position that is comfortable: sitting, reclining, or lying on the left side with pillows to support and flex knees. A variety of restful images may be used (gentle waves, swaying palms, sunny beaches) to encourage relaxation, or the patient may imagine a warming sensation passing downward from the top of her head to her toes to induce a feeling of calm. Rhythmic, restful breathing can be included to encourage deeper release of striated muscles and calming of the mind. Learning to release tension during pregnancy helps the woman to conserve her energy and reduce fatigue. With diligent practice, relaxation becomes a skillful tool in meeting the demands of childbirth by enabling the woman to remain calm, reduce fatigue, and reduce pain perception during labor and birth. In the puerperium, relaxation skill provides an invaluable tool for counteracting the fatiguing role of parenting, with its demands of caring for the baby while enduring lack of sleep. As such, it should be included in every exercise session, used as a means to cool down after exercising, and encouraged prior to retiring to ensure more restful sleep.

Although opinions differ, the scientific studies that have been published regarding the effects of maintaining involvement in sports activities during pregnancy have been mostly positive. Most physicians have been almost unanimous in their belief that it is not necessary for a pregnant woman to limit her activities, provided that she does not become fatigued, experience pain, or lose balance and has no contraindications to the activity. All adults need exercise, and failure to obtain exercise can result in weakness or illness. This is particularly true for those pregnant women who are normally active or who are sports enthusiasts. Marked restriction of such activities shifts the emphasis during pregnancy from the normal physiologic experience toward one bordering on illness. Lengthy periods of enforced idleness can be detrimental to a woman's physical and mental well-being; therefore, any sport or exercise in which the woman has engaged for a long time is permissible, with caution not to continue to the point of fatigue or pain.

Physicians strongly agree that pregnancy is not the time to learn a new sport. An exception would be changing from a weight-bearing to a non-weight-bearing activity, such as from running or jogging to swimming or water aerobics.^5,38,60 Pregnant women are also cautioned not to indulge in competitive sports or anything that would cause continuous panting or fatigue. Because of postural realignment, focus on the new body image is important so that balance is not impaired. Some physicians believe that balance is more precarious in the latter part of the third trimester and that women do not respond as quickly in a stress situation.

For this reason, physicians advise against activities that require quick decision-making and balance, such as skiing, skating, and rollerblading. Cross-country skiing has become increasingly popular for pregnant women in cold climates, but again, heat restriction, pacing, adequate breathing, and ability to balance are important.

Walking with well-fitted, low-heeled shoes or sneakers with cushioned soles, performed while observing good posture, is the exercise most prescribed by obstetricians. Hydration and nutrition must be maintained for extended walks. Additionally, walking should be preceded and followed by stretching.

Swimming is an excellent choice for activity, because the woman is in a state of weightlessness, with less pressure on her circulation. She can pace herself, going as fast or as slow as she desires while maintaining her comfort level and relaxed breathing pattern.

Tennis is another popular sport played by pregnant women without ill effects, but self-tolerance, heat restrictions, ample hydration, and noncompetitive settings are key. Curtailing the need to reach far-flung balls is imperative in advancing pregnancy, and avoiding sharp turns is advised. Playing doubles is recommended over singles.

Bicycling is another form of non-weight-bearing exercise that can be enjoyed by the pregnant woman if she is accustomed to the activity and can pace herself and maintain her balance. Wearing a helmet is imperative, and knowing the location of restrooms along the way is a must.⁵⁷ If fear of falling is a problem, a stationary bicycle can be used. This activity is beneficial to the cardiovascular system while sparing the joints and ligaments.

Golf remains a favorite with some pregnant women who play regularly. This activity involves walking and well as arm movements and balance.

Horseback riding has historically been considered dangerous because of the bouncing movements and possibility of being thrown and is not recommended.

Running and jogging have come under scrutiny both in the general and the pregnant population. Many orthopedic surgeons decry possible harm to ligaments of the back, hips, knees, and ankles. These are under strain during pregnancy because of hormonal changes and increased body weight; therefore, pregnant women—even those who were regular runners—need to be cautioned to run only if they are in good condition, wear well-fitting and well-conditioned shoes, stretch before and after running, never run on concrete, and above all be aware of their bodies and stop when they become fatigued or experience pain.^{22,26,41,58,59}

In all sports activities, if a woman has long been a devotee, is proficient, is prepared to slow down or stop the activity when she becomes fatigued, and understands how pregnancy changes affect her joints and muscles, she should be encouraged to maintain her involvement.⁶⁴ Good body mechanics should be used in all activities, and good sense regarding safety, balance, heat restrictions, and tolerance is mandatory.

Contraindications for Sport Activities

Women with conditions such as pre-eclampsia, toxemia, placenta previa, or heart conditions, for which rest is the main mode of treatment, are obviously advised not to indulge in vigorous physical activity. Liberal amounts of rest have been said to improve the prognosis of high-risk pregnancies associated with these conditions or hypertension. There is evidence, however, that extended lying in the supine position is detrimental during pregnancy, because compression of the vena cava lowers the arterial pressure through decreased venous return to the heart. As a result, renal plasma flow and uterine blood flow are decreased. However, extended prescribed bed rest without qualification regarding position could also have detrimental effects on muscle tone, back pain, reduced circulation, and emotional state. To maintain circulation and muscle tone, these patients could be prescribed mild bed exercises administered by a qualified physical therapist.

Exercise stimulates blood flow to the muscles, particularly the extremities, and it has been speculated that uterine flow may be diminished to some degree during strenuous activity. However, there is no evidence that periods of moderate exercise compromise the fetus in any way in a normal pregnancy. There is some justification for curtailment of activity in women with incompetent cervix or when frequent bleeding occurs. Otherwise, most physicians agree that the psychological benefits of exercise outweigh these speculative problems. The main guide is for the woman to “listen” to her body signals and use common sense and sound judgment.