Does Exercising When Pregnant Hurt The Baby?

 No.

This has been a hot topic of late, and the answer to the question of "Does Exercises When Pregnant Hurt the Baby?" is an emphatic NO.

Not only does it not hurt the baby, it actually improves blood flow to the placenta and is AMAZE-BALLS for the person growing the baby in their belly. I'll give summaries of a few personal fav studies in both layman's text, and also include the reference, for Geek's like me!

Exercise Doesn't Harm the Baby

First of all, let's start with the studies that show that exercise during pregnancy does not lead to lower birth weights or other negative effects.

1. This cool Danish study found no negative effects on baby in mother's who exercised regularly during pregnancy.  WOOT!  
2. Another neat study found no negative effects on baby in mom's who exercised, even if the caloric intake wasn't as high as was ideal. That doesn't mean that there wouldn't be negative effects for mama in that case, so let's be sure to get enough fuel in your tank, people.  

But here's the thing...these studies are from 2006 and 2010---does your OB-Gyn know about these studies?  They honestly might not, so it might be up to YOU  to educate yourself, and your medical team, about the benefits of exercise.  

Benefits for the Baby

Numerous studies have shown that not only is exercise not harmful to the baby, but that it is actually beneficial!

1. The LeMoyne Study was a randomized controlled trial that showed that babies whose mother's exercised prenatally had increased brain activity from days 8-12 when compared to babies whose mothers did not exercise while pregnant!  This means that if you exercise when pregnant, your baby's brain will be more active after birth, than a baby of someone who didn't exercise.  
2. The Dominiques Study showed improved IQ scores at ages 1, 2 and 4 in babies whose mothers exercised while pregnant!  So if you exercise when you are pregnant, your kid will be smarter than if you didn't exercise!!

Benefits for the Person Growing the Baby

1. The same Danish Study that showed no negative effects for baby also showed reduced birth length in people who exercised while pregnant!
2. The Hinman Study was a Review that showed MANY benefits, including reduced risk of Cesarean delivery, and shortened second stage of labor (the part when the baby is coming down and you push it out).  So exercise in pregnancy MIGHT help you with an easier delivery!!  (and perineal massage, and learning to relax your pelvic floor WILL  help you with an easier delivery--check out Push Prep for more juicy deets). 

We will have to talk another time about what exercises are appropriate, though. And how something like, say, running, at a certain point in pregnancy won't hurt baby....but might be a big load on mama's feet and spine and pelvic floor...but that's for another time.

Thanks for being here!  I hope this helped you understand some of the basic benefits of exercising in pregnancy, as well as "myth-busted" some common misconceptions.  Please follow me on Instagram and consider signing up for my mailing list for more tips on exercising in pregnancy (and beyond!).  

And If you are looking for more, Push Prep is a delivery focused course, and The Pregnancy Course includes Bump Lab, a 2-hour Pregnancy Class that teaches you things that actually matter (like what's happening to you and baby, how much extra calories do you really need, and how to stay active in the bedroom as pregnancy progresses), Pregolicous, a masterclass for problem solving many "common not normal" pains in pregnancy, and of course Weight Lifting in Pregnancy, a course for how to get, or stay active as your pregnancy progresses.  Weight Lifting in Pregnancy includes full workouts, as well as bite-size workouts and common substitutions for programming.  You don't want to miss them :) 

Geek Squad: Study Links

The Danish Study: Juhl M, Olsen J, Andersen PK, Nohr EA, Andersen AM. Physical exercise during pregnancy and fetal growth measures: a study within the Danish National Birth Cohort. Am J Obstet Gynecol. 2010;202(1):e61–e68.

The Study that showed no deficits in birth weight in mothers who exercised, even if their caloric intake was lower than ideal. Giroux I, Inglis SD, Lander S, Gerrie S, Mottola MF. Dietary intake, weight gain, and birth outcomes of physically active pregnant women: a pilot study. Appl Physiol Nutr Metab. 2006;31(5):483–489.

The LeMoyne Study: LeMoyne EL, Curnier D, St-Jacques S, Ellemberg D. The effects of exercise during pregnancy on the newborn’s brain: study protocol for a randomized controlled trial. Trials. 2012;13:68.