How much physical activity is safe and healthy for pregnant women?

We will be discussing: Physical activity and the risk of preterm birth: a systematic review and meta-analysis of epidemiological studies by Aune and colleagues.

Wednesday 30th August 2017, 8pm BST

Scenario
The first patient on the afternoon clinic schedule is seeing you for her first
obstetric visit. She is a healthy nulliparous 37-year-old business
administrator. She asks whether her morning workout routine will increase the
risk of preterm delivery.

What recommendations do you make about time and intensity of exercise during
pregnancy?

Description of research

Participants: Pregnant women in prospective studies of physical activity in
pregnancy.
Outcomes: Preterm birth <37 weeks
Study Design: Systematic review and meta-analysis of 41 studies from Europe, North America, South America, Asia, Australia and New Zealand
Authors’ conclusion: Higher leisure-time physical activity in pregnancy is associated
with a 14% relative risk reduction in preterm birth <37 weeks of gestation compared to lower physical activity. The data does not definitively answer the question of “how much” exercise is enough, or too much, but the lowest observed risk for preterm
birth was at 2-4 hours of activity per week.

Discussion points

  • How do you counsel women on physical activity in pregnancy?
  • Do you give the same advice about exercise to women who are underweight? How about those who are overweight or obese?
  • What is the most important conclusion of this study, from a patient-counselling standpoint?
  • Some of the forest plots (e.g Figure 4e) suggest that RCTs and cohort studies give different answers to a clinical question. Is this common in women’s health research? Can you name prominent examples where observational data gave an “opposite” or “wrong” answer to an important clinical question?
  • Describe the difficulties in studying this topic. How could you design the “perfect study” to answer the question of “how much” physical activity is safe and healthy for pregnant women?

Suggested reading

1. Perales et al. Exercise during pregnancy. JAMA 2017;317(11):1113-4.
2. Magro-Malosso et al. Exercise during pregnancy and risk of preterm birth in overweight and obese women: a systematic review and meta-analysis of randomized controlled trials. Acta Obstet Gynecol Scand 2017; 96:263-273.