"Susan," age 30, was pregnant for the first time. At her initial prenatal visit, she reported experiencing sleeping difficulty, mild anxiety and sciatic nerve pain. Further discussion indicated that Susan's anxiety was linked to having limited social supports, since she and her partner had only recently moved to the area. Susan was healthy, and her history revealed no significant medical conditions. At the end of her visit, her nurse practitioner recommended a prenatal yoga class as a strategy for coping with the typical discomforts of pregnancy.

At her next appointment a month later, Susan enthusiastically talked about the prenatal yoga class. While her sciatic nerve pain wasn't completely gone, she reported feeling significantly better overall. She was sleeping well at night and reported having increased energy. She also described happiness about developing friendships with the other pregnant women in her class, and she stated that this increased sense of community had helped decrease her anxiety about her pregnancy.

As a form of exercise, stretching and relaxation, yoga has become immensely popular in the United States over the past 20 years.¹ Approximately 36 percent of the U.S. population now uses some form of complementary and alternative medicine (CAM), a category in which yoga is an established therapeutic form.² An estimated 15 million Americans have practiced yoga at some point.³ Many pregnant women use yoga to increase flexibility, enhance breathing techniques and learn relaxation techniques in preparation for childbirth.

Millions of pregnant women who use complementary or alternative medicine therapies often do so without informing their obstetric providers. As the popularity of yoga continues to grow, health care professionals should be prepared to make recommendations to their patients about participation in yoga programs during pregnancy.

Yoga and Pregnancy
The practice of yoga has many positive effects on pregnant women. Yoga is a multifaceted approach to exercise that encompasses physical stretching, mental centering and breath awareness, making it an ideal preparation for labor and childbirth. Yoga encourages relaxation, internal focus and slowed breathing patterns, goals that are common in many types of childbirth preparation classes. Yoga may help relieve many of the common discomforts of pregnancy, such as lower back pain, nausea, insomnia, carpal tunnel syndrome and headaches.^4,5 In addition, prenatal yoga classes often offer a supportive environment in which pregnant women can share their experiences, which may help relieve feelings of anxiety or depression.

Specifically, research suggests that yoga can help ease the musculoskeletal consequences of pregnancy while preparing the muscles of the lower body for use in childbirth.⁶ The breathing techniques used in yoga can help reduce or manage the shortness of breath that may accompany pregnancy and teach women how to breathe through physically challenging experiences such as labor.⁷ Yoga encourages pregnant women to be mindful of the body's innate capacities and to recognize the connection among mind, body and breath. Yoga techniques also may be useful in promoting postpartum recovery and coping with the stresses of parenting.⁶

Recent studies show that yoga during pregnancy is safe for most healthy women and may not increase the risk of complications. Women who participate in daily yoga practice have decreased rates of intrauterine growth retardation and decreased rates of pregnancy-induced hypertension and may have decreased rates of preterm delivery.⁴

Because yoga involves movement of the body and can be considered a type of exercise, it is helpful to examine research about exercise in pregnancy. A review of the literature reveals that most kinds of gentle exercise during pregnancy may help decrease rates of pregnancy-induced hypertension, gestational diabetes, low back pain and symptoms of carpal tunnel syndrome, and reduce fatigue, anxiety and depression.⁸

The American College of Obstetricians and Gynecologists (ACOG) provides guidelines for general exercise during pregnancy. ACOG has concluded that almost all women with uncomplicated pregnancies can benefit from exercise. Women with numerous complications should be cautioned against strenuous exercise; for example, exercise by women with uncontrolled hypertension is contraindicated.⁹

The versatility of yoga suggests that it is more suitable for pregnant women with chronic conditions than other types of exercise. Research shows that the breathing patterns of yoga may have benefits even for patients with chronic hypertension, asthma and anxiety.^10,11 Studies of exercise during pregnancy have documented few to no adverse effects in pregnant women or their developing fetuses.^8,12-15

Furthermore, group exercise classes that include physical movement and the presence and support of other antepartum women may reduce the incidence of postpartum depression.⁸

General Yoga Benefits
Yoga is a beneficial complementary therapy for many medical conditions. Many common discomforts of pregnancy cause symptoms that are similar to those that surface in other medical conditions. Because yoga is used for symptom management in these disease states, it is not unreasonable to infer that yoga's benefits may also carry over to help with similar discomforts of pregnancy.

The health of a wide range of people may be improved with regular yoga practice. The practice of hatha (gentle) yoga can increase strength, endurance, flexibility and overall physical fitness.¹⁶ Patients with hypertension may benefit from yoga therapies; researchers have documented statistically significant decreases in systolic and diastolic blood pressures and mean arterial pressures, suggesting that yogic practices may have long-term benefits on health.^10,11

Cardiac patients who practice yoga experience an overall enhanced sense of well-being, decreased anger tendencies and an improved sense of meaning in life.¹⁷ In an often-cited report, patients with asthma were randomized to receive yoga training or continue with regular medication use. The researchers documented significant improvements in the yoga group, which had fewer and less severe asthma attacks.¹⁸ Finally, multiple randomized, controlled trials recently demonstrated that yoga may be effective in significantly reducing chronic back pain.^19,20

Forms of Yoga
Numerous types of yoga programs and classes are available, including prenatal yoga, hatha yoga, iyengar yoga, Bikram yoga, ashtanga yoga and others. Although yoga is a type of exercise, it is not typical of all exercise. For example, yoga involves more than mere physical posture changes and the exertion that are integral to typical American ideas of exercise.

Three yoga tools are commonly used: asanas (poses), pranayama (control of breath) and meditation. Each principle is essential to all yoga, but some types of yoga emphasize certain tools more than others. One goal of yoga, especially prenatal yoga, is to focus on body awareness. This involves a concentration on uniting the breath and the body through movement and balance in poses. Asanas can be modified in intensity and position to best fit the person performing them.

Prenatal yoga is a gentle form of hatha yoga, in which instructors are aware of the various needs of the pregnant woman and are able to adapt poses to fit these needs.

Not all types of yoga are appropriate for pregnancy. For example, ashtanga yoga and power yoga involve difficult poses and tend to be more strenuous, and Bikram yoga takes place in rooms set to an ambient temperature of up to 100 degrees Fahrenheit. Unless the woman is an experienced yoga practitioner, these forms of yoga are typically not recommended during pregnancy.

Additionally, certain poses are discouraged at various times during pregnancy; a qualified prenatal instructor can guide a patient through safe practices. Finally, strenuous exercise should be avoided if a pregnant woman has a history of miscarriages, a herniated disc or other back injury, or cervical insufficiency.⁹ Health care professionals must ensure that patients who wish to pursue a yoga exercise routine are aware of these caveats.

Guidance for Health Care Professionals
Table 1 provides an assessment tool to determine a patient's ability to use yoga for relaxation, mindfulness and exercise. The assessment findings assist in determining whether to recommend or discourage the practice of prenatal yoga and provide for the tailoring of recommendations to meet the needs of the individual woman.

The pregnant woman who is deemed eligible for yoga practice requires education about the types of yoga and the possible benefits (Table 2). Table 3 provides safety information to be shared with patients who decide to pursue yoga during pregnancy.

Expected outcomes of prenatal yoga practice are increased relaxation, increased sense of well-being and decreased symptoms related to common discomforts of pregnancy.

Putting It Into Practice
Published guidelines for prenatal yoga are somewhat limited by an insufficient quantity and quality of research. The ethical implications of controlled experimentation on pregnant women prevent tightly controlled studies. Therefore, evidence-based articles on the nonpregnant population and research about exercise during pregnancy form the foundation of the recommendations contained in this article.

Little research has been done on populations other than healthy pregnant women, so whether pregnant women with complications may benefit from yoga or another form of exercise is unclear. The recommendations contained in this article should be updated as research becomes available, and as feedback is received from health care professionals, patients and yoga instructors.

References
1. Tindle H, et al. Trends in use of complementary and alternative medicine by US adults: 1997-2002. Altern Ther Health Med. 2005;11(1):42-49.

2. Barnes P, et al. Complementary and alternative medicine use among adults: United States, 2002. DHHS Publication No. 2004-1250-04-0342. 2004. Hyattsville, Md.: U.S. Department of Health and Human Services; 2002.

3. Saper R, et al. Prevalence and patterns of adult yoga use in the United States: results of a national survey. Altern Ther Health Med. 2004;10(2):44-49.

4. O'Connor D, et al. Nonsurgical treatment (other than steroid injection) for carpal tunnel syndrome. Cochrane Database Syst Rev. 2003;1:CD003219.

5. Wang SM, et al. Complementary and alternative medicine for low-back pain in pregnancy: a cross-sectional survey. J Altern Complement Med. 2005;11(3):459-464.

6. Collins C. Yoga: intuition, preventive medicine, and treatment. J Obstet Gynecol Neonatal Nurs. 1998;27(5):563-568.

7. Narendran S, et al. Efficacy of yoga on pregnancy outcome. J Altern Complement Med. 2005;11(2):237-244.

8. Impact of physical activity during pregnancy and postpartum on chronic disease risk. Med Sci Sports Exer. 2006;38(5):989-1006.

9. American College of Obstetricians and Gynecologists. Exercise during pregnancy and the postpartum period. Clin Obstet Gynecol. 2003;46(2):496-499.

10. Schein M, et al. Treating hypertension with a device that slows and regularizes breathing: a randomised, double-blind controlled study. J Hum Hypertens. 2001;15(4):271-278.

11. Grossman E, et al. Breathing-control lowers blood pressure. J Hum Hypertens. 2001;15(4):263-269.

12. Clapp J. A clinical approach to exercise during pregnancy. Clin Sports Med. 1994;13(2):443-458.

13. Clapp J, et al. Beginning regular exercise in early pregnancy: effect on fetoplacental growth. Am J Obstet Gynecol. 2000;183(6):1484-1488.

14. Bungum TJ, et al. Exercise during pregnancy and type of delivery in nulliparae. J Obstet Gynecol Neonatal Nurs. 2000;29(3):258-264.

15. Kramer MS, McDonald SW. Aerobic exercise for women during pregnancy. Cochrane Database Syst Rev. 2006;3:CD000180.

16. Tran MD, et al. Effects of hatha yoga practice on the health-related aspects of physical fitness. Prev Cardiol. 2001;4(4):165-70.

17. Kennedy J, et al. Changes in spirituality and well-being in a retreat program for cardiac patients. Altern Ther Health Med. 2002;8(4):64-73.

18. Nagarathna R, Nagendra HR. Yoga for bronchial asthma: a controlled study. BMJ. 1985;291(6502):1077-1079.

19. Sherman K, et al. Comparing yoga, exercise, and a self-care book for chronic low back pain. Ann Intern Med. 2005;143(12):849-856.

20. Williams K, et al. Effect of iyengar yoga therapy for chronic low back pain. Pain. 2005;115(1-2):107-117.

Patricia Kinser is a women's health nurse practitioner who is a member of the faculty at Bon Secours Memorial School of Nursing in Richmond, VA. She is a certified prenatal yoga instructor at 4025 Yoga & Wellness in Richmond. Reach her at prenatalyogarichmond@yahoo.com. Carrie Williams is a women's health nurse practitioner in Charlottesville, VA.

Table 1: Assessment for the Practice of Yoga During Pregnancy^7,10

Identify patients who may benefit from low-impact exercise during pregnancy.

• Pregnant patients with minimal obstetric or medical complications
• Obese pregnant patients who have or are at increased risk for developing gestational diabetes
• Pregnant patients who would like to relieve common discomforts of pregnancy and connect with other pregnant women

Identify patient's readiness to adopt a yoga exercise program.

Identify medical contraindications to participation in prenatal yoga classes.

• Heart disease that adversely affects circulation
• Restrictive lung disease
• Cervical incompetency or cerclage
• Increased risk for preterm labor or presence of preterm labor
• Persistent second or third trimester bleeding
• Placenta previa after 26 weeks' gestation
• Ruptured membranes
• Herniated disc or back injury

Identify appropriate and inappropriate types of yoga for patients.

Identify community resources and accessibility of yoga classes.

Table 2: Education Points About Yoga^{5,10-12,16,18,19}

Educate women and their partners about types of yoga:

• Prenatal or hatha (gentle) yoga may be the most appropriate forms.
• Bikram (hot) yoga may cause hyperthermia.
• Ashtanga yoga and similar types of "power" yoga may be too strenuous for women who are not already yoga practitioners.

Educate women and their partners about possible benefits of prenatal yoga:

• Possibility for increased flexibility, strength and endurance of childbirth musculature
• Possibility for a greater sense of well-being
• Possibility of decreased likelihood of cesarean birth
• Possibility for decreased ligament and joint pain, such as reduced carpal tunnel syndrome symptoms
• Possibility for decreased blood pressure in patients with hypertension
• Possibility for decreased shortness of breath and improvement of symptoms for patients with asthma
• Possibility for reduced anxiety
• Possibility for improved self-image

Table 3: Safe Yoga Practice in Pregnancy

• Practice in a well-ventilated room to avoid overheating.
• Bend from the hips, not the back, to maintain normal spine curvature.
• Avoid poses such as deep forward or backward bends, which may overstretch the abdominal musculature.
• Avoid twisting poses that put undue pressure on the abdomen. Modify these poses to twist only the upper back, shoulders and rib cage.
• Inexperienced yoga practitioners should avoid inverted poses.
• Drink plenty of fluids.
• As the belly grows, stabilize with yoga props to accommodate changes in the center of gravity.
• Pay attention to the body's cues. Stop at any significant discomfort; consult the yoga instructor and health care professional.