Evidence-Based Medicine or Opinion: Exercising Pregnant

I recently listened to a podcast by Freakenomics: Bad Medicine, Part 1: The Story of 98.6 which introduced me to the term “Evidence-Based Medicine”. While listening to it, I started wondering about the current recommendations for pregnant women and exercise and how they came to be.

I highly recommend listening to the episode “Bad Medicine” but for the purposes of this blog post, you only need to know what Evidence-Based Medicine (EBM) is. Stealing from Wikipedia “EBM is an approach to medical practice intended to optimize decision-making by emphasizing the use of evidence from well-designed and well-conducted research.” Sounds reasonable, right? That’s what medical professionals do and how medical recommendations come to be, right? Well, not always – and unfortunately not until relatively recently (as in, the concept of EBM was first introduced in the 70s).


Stealing from Wikipedia again, Cochrane, previously known as The Cochrane Collaboration, was founded by Iain Chalmers (featured in the Freakenomics episode above) in 1993. Cochrane’s mission is “to promote evidence-informed health decision-making by producing high-quality, relevant, accessible systematic reviews and other synthesized research evidence.”

Unfortunately, Cochrane’s review of studies and research done in relation to aerobic exercise for pregnant women uncovered that there was insufficient data to make confident recommendations. More specifically, the conclusion is:

Regular aerobic exercise during pregnancy appears to improve (or maintain) physical fitness. Available data are insufficient to infer important risks or benefits for the mother or infant. Larger and better trials are needed before confident recommendations can be made about the benefits and risk of aerobic exercise in pregnancy.


I found a review done by the Columbia University College of Physicians and Surgeons that examined the quality of evidence that underlies the recommendations made by the American College of Obstetricians and Gynecologists (the College); their conclusion:

One third of the recommendations put forth by the College in its practice bulletins are based on good and consistent scientific evidence.

For obstetrics, specifically, only 25.5% of recommendations met the same criteria.

What are the rest of the recommendations – the majority? They’re based on either inconclusive/poorly done studies or merely the opinion of a group of physicians.

For an example, in 1985, the College’s recommendation was that pregnant women should not allow their heart rates to exceed 140 beats per minute. This recommendation came from consensus opinion of a panel of obstetricians. (This recommendation was revised in 1994 and the heart rate limit was lifted for pregnant women entirely.)


Obviously, I’m quite liberal on the whole exercise during pregnancy front. While I am very interested in the opinions of medical professionals, when we are talking about opinions (and not facts or evidence-based medicine), my opinions about my body are greater than anyones.

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