What to tell patients about exercise in pregnancy

If we had a magic pill to reduce rates of pregnancy complications and improve the health of pregnant patients, we would prescribe it faster than Allyson Felix can sprint 400 meters. Exercise during pregnancy isn’t a magic pill, but the potential benefits of engaging in purposeful physical activity during all stages of the reproductive journey far outweigh the perceived risks. Family physicians have a unique opportunity to assess health behaviors of patients before, during, and after pregnancy and provide guidance around lifestyle changes in the context of families and communities.

Before discussing the benefits and considerations for leisure-time physical activity in pregnancy, it is important to note that not every pregnant patient has the privileges of time or safety required to include exercise in their daily routine. The burden of societal inequity, systemic racism, misogyny, and climate change falls hardest on Black, brown, Indigenous, and people of color, especially during pregnancy. Acknowledging these barriers, we can encourage patients through individual relationships while advocating for policy changes to support our communities.

All adults, including pregnant patients without contraindications, are recommended to engage in 150 minutes per week of moderate intensity physical activity for optimal health. Exercise in pregnancy is associated with lower rates of prenatal complications, better fetal outcomes, and gentler labor experiences and postpartum recovery. Studies have found lower rates of gestational diabetes and large for gestational age infants, gestational hypertension, and preterm delivery among exercising pregnant patients compared to those who did not exercise. One study found that people with higher physical activity levels during pregnancy had a shorter duration of active labor. Another systematic review and meta-analysis of 17 trials found a reduction in cesarean birth rate of 16% in the exercise group. Exercise is well-known to improve mood regulation and is associated with fewer symptoms of postpartum depression. Considering the biomechanical changes of pregnancy, at least 60% of pregnant patients experience musculoskeletal pain, but greater self-reported overall fitness is associated with lower levels of bodily pain, lumbar/sciatic pain, and reduced pain disability in the second and third trimester.

How should we talk to patients about exercise during pregnancy? Previously inactive patients can begin exercising with gradual increases in frequency and duration over time. Anyone physically active prior to pregnancy can continue throughout pregnancy, but will likely need to modify activities to adapt to physiologic and biomechanical changes over time. With the right support in place, elite athletes can partner with their care teams and coaches to prioritize a healthy pregnancy and athletic longevity. Almost all types of aerobic exercise are safe (walking, jogging, swimming, cycling), but pregnant patients should avoid activities with higher risk of blunt abdominal trauma. Patients should be counseled to take breaks when needed, get enough to eat and drink, avoid extreme heat, and stop exercise immediately if vaginal bleeding or contractions occur. Most people should aim for intensity <80% of their maximum heart rate (or <15 “hard” on the rating of perceived exertion scale).

People with certain obstetric and medical conditions, particularly cardiovascular/respiratory complications, should be more cautious with exercise during pregnancy and the primary obstetric care team should have a low threshold to consult with maternal-fetal medicine.

AFP has been discussing exercise in pregnancy before it was cool (1998), and the American College of Obstetricians and Gynecologists updated their clinical guidance in 2020 with helpful tables for counseling. Our July issue includes a FPIN Clinical Inquiry on reducing risk of hypertensive disorders of pregnancy with exercise and an article on care of the active female with recommendations for exercise in pregnancy and the postpartum period in this Table (subscription required). Encouraging and facilitating exercise during pregnancy, particularly for those with societally imposed barriers, is an important component of working toward health equity for pregnant patients.

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Dr. Fredrickson is a third-year resident at the University of Washington Family Medicine Residency Program, Seattle and one of AFP's 2022 Resident Representatives.