Can I Lie on My Back During Pregnancy?

"Hi! I recently saw one of your videos for exercises to do during pregnancy and noticed the woman in the video seems very far along. She's on her back doing glute bridges, and I was wondering if that's OK at that stage of pregnancy? I've been told you shouldn't lie on your back after 20 weeks. Thanks, by the way for all of the great information you put out!" — Claire W.

Hi Claire! Thanks so much for your kind words and your question. This is one of the most frequently asked questions we're asked when it comes to pregnancy and exercise. This, and so many other questions for which women often can't get a definitive answer, are why we have created the Moms Gone Strong program, the most well-researched, comprehensive, pre- and postnatal exercise and nutrition program ever written, as well as the Coaching & Training Women Academy, which offers the world’s first evidence-based, body-positive, interdisciplinary Pre- & Postnatal Coaching Certification.

We want to help women and the coaches who work with them to understand what's safe during pregnancy and what's not, and we want to combine research and practical experience to help women have the happiest, healthiest, safest, and strongest pregnancy and postpartum experience possible.

In the past, physicians have advised women to not to lie on their backs because the weight of the baby could press on, and block, the mother’s vena cava, the main vein that carries blood back to the heart from the lower body, and some recommendations say that after week 16, a woman should avoid lying flat on her back for long periods of time [1]. However, “long periods of time” is not clearly defined, and 2006 research published in BJOG, shows that uterine blood flow decreases when women lie on their backs, although during supine exercise, the decrease is about half of what it is during supine rest [2].

Current guidelines from Sports Medicine Australia suggest avoiding exercise in the supine position after 28 weeks [3]. However, more recently, some research [4] has stated that as long as a woman feels OK while lying on her back, and she doesn’t feel lightheaded or nauseated, tingling in the legs, general discomfort, and her breathing is not impaired during or after the bout of exercise or stretching, she should be fine to lie on her back.

You can see that there are some differences depending on which guidelines you read. If you do perform supine exercises, or program them for a client, check in regularly to make sure none of the symptoms listed above appears.

These guidelines seem to change quite frequently as the science changes and we learn more, so be sure to check them regularly and stay informed. Most women will probably be fine especially if they monitor how they feel, but if you want to be ultra-safe, you can avoid the supine position after 24–28 weeks or work a 15 percent incline.