Monday, May 22, 2017

Strength Training and Pregnancy: The Real Risk

We don't live in a world where there are usually only two options...even if it seems that way. High school graduates don't have to choose from the only two local colleges. Saying "no" to vanilla doesn't mean we're eating chocolate.

With any activity during pregnancy, a common thought is to "take it easy." The insinuation is the opposite (high-effort activity) is dangerous. This may explain why more than 60% of expectant mothers remain sedentary throughout pregnancy (1). It is possible that higher-intensity exercise could be dangerous for the mom and fetus. However, there is a third option: challenging exercise that is thoughtfully planned, beneficial, and safe.

Not only should pregnant women perform challenging exercise, but exercising is the safest way to go...for the mom and the fetus. Specifically, strength training during pregnancy is extremely valuable to both parties involved. In fact, I feel strength training should become the default for expecting mothers.

Value for the Mom

Pregnancy is a risky period for the mother. If the mother is inactive, she could gain an excess of weight and lose a large amount of muscle (1). These changes are often never corrected (1). The expecting mother also could develop gestational diabetes, which increases the risk for eventual type 2 diabetes (1,3).

So...why should expecting moms strength train?

Women who strength train during pregnancy gain less weight (1). Strength training improves or maintains posture and strengthens key muscles involved with labor (2). It's no surprise that labor strain is less for these women (2). Strength training may accelerate recovery from giving birth and is connected with a lower rate of operational births (2). Lower back pain is also much less common for expecting mothers who strength train (1).

Exercise in general reduces the risk of preeclampsia by 24% (1). However, high-intensity exercise, which is what strength training is, reduces the risk by 54% (1)! In other words, high-intensity exercise prevents one out of every two women from suffering preeclampsia. 

For women who develop gestational diabetes, strength training reduces or eliminates the need for insulin (1,3). This is especially noteworthy since insulin treatments increase the risk for the newborn being undersized for at least the first few years of life (3). Weight training improves post-meal and fasting blood glucose, too (3).

Value for the New Life

Strength training during pregnancy enhances the mom's status as a benefactor for the baby (you know, in addition to the fact that she's doing the baby a solid by hosting him or her for nine months).  

Babies from strength-trained moms are generally longer and have more lean mass (1). A study of five-year-olds from groups of moms who did or did not strength train also provided other possible insights (1). Offspring from trained moms were more attentive, disciplined, and showed better overall neurological development (memory, emotional development, etc.).


None of these benefits matter if strength training isn't safe for the expecting mom and fetus. Fortunately, it is. Common exercise concerns during pregnancy are trauma to the fetus, hyperthermia (elevated body temperature), and disruptions of regular blood flow to the uterus (2). Strength training does not cause any of the three to occur (1,2). Strength training, or any general high-intensity exercise, does not increase the risk of a miscarriage or any negative labor side effects (1).

My Experiences and Recommendations

I strongly feel exercise, especially strength training, should be the default for expecting moms unless informed otherwise by the personal OB/GYN. It's the safest way to go for women during pregnancy.

Based on the research and my personal experience with training pregnant women, here are a few practical recommendations:
  1. This article, especially these recommendations, assumes the pregnancy isn't high-risk. Seek the opinion and clearance of the personal OB/GYN before proceeding with anything relating to exercise. The recommendation of the OB/GYN trumps anything shared here.
  2. After the first trimester, avoid prone and supine positions (lying facing down or up).
  3. After the first trimester, avoid overhead lifts. These lifts might add stress to the lower back (1) and also significantly increase blood pressure.
  4. Breathing continuously throughout an exercise is especially critical during pregnancy. Holding one's breath increases blood pressure, and that could harm the fetus (2).
  5. Move continuously between sets to avoid blood pooling in the veins.
  6. Due to an increase in the hormone elastin, ligaments become more flexible during pregnancy. If the mother stretches, avoid pushing the stretch the whole way. Doing so could lead to long-term tissue damage with the more lax, damage-susceptible ligaments.
  7. With the previous point in mind, go to a comfortable but not full range of motion on hip adduction and abduction machines in the second and third trimesters.
  8. Due to the greater risk of potential fetus trauma and bone/ligament/tendon injury, researchers recommend avoiding lunges, back squats, and stiff-legged deadlifts (2). (I personally trained most pregnant clients on machines and cables.)
  9. For mothers with healthy, low-risk pregnancies, I've trained them close to complete muscle fatigue with challenging weights and controlled movements on each set...into the start of the third trimester...with no ill effects. Effort is not dangerous for women in healthy pregnancies. Poor exercise choices and breath-holding are dangerous.


  1. Schoenfeld, B. (2011). Resistance training during pregnancy: safe and effective program design. Strength & Conditioning Journal, 33(5), 67-75.
  2. Pujol, T. J., Barnes, J. T., Elder, C. L., & LaFontaine, T. (2007). Resistance training during pregnancy. Strength & Conditioning Journal, 29(2), 44-46.
  3. Brankston, G.N., Mitchell, B.F., Ryan, E.A., & Okun, N.B. (2003). Resistance exercise decreases the need for insulin in overweight women with gestational diabetes mellitus. Elsevier, 190, 188-193.


Anonymous said...

Insightful article, clearly there are more benefits to continue to stay active then not to. Unfortunately, I believe some women still feel as though they get a free pass to eat unhealthy and not continue with a workout routine. Articles like this one are perfect to help with educating and encouraging women to maintain a healthy lifestyle even when pregnant.

Dr. Sean Preuss said...

Thank you for reading and for the kind words.

I'm hoping exercise during pregnancy will become the norm. Considering the possible benefits on the newborn, exercising (and eating nutritious foods) during pregnancy should be taken very seriously.

Anonymous said...

Great article! I found the studies you gave to be very helpful. Our human bodies are extraordinary in how they adapt so well to change. If only our mindset would be just as open to change then life would be a little easier. Sean, you provide valuable information with these gems of articles you produce, thank you. This article in particular speaks to me because I've gone through several pregnancies, and each one was a different experience. My last pregnancy I truly felt like Wonder Woman as I lifted heavy weights throughout my pregnancy. Which, by the way is a spectacular film. I felt and saw the benefits of staying active during each trimester. I wish all woman would have the limitless mindset, and the importance of staying healthy in all areas for themselves and for their young.

Wonderful article Sean, thank you!

Dr. Sean Preuss said...

Hi Anonymous,
Thanks for reading and for the sweet words. I love hearing that you lifted throughout your last pregnancy. Have you noticed any neurological "advancements" (memory, awareness, etc.) in your youngest?

And yes, I agree: Wonder Woman is a great film! :)