Thursday, March 15, 2012

Jumping while Pregnant will NOT cause Brain Damage

The moron that commented on my 12.3 video had some more insight.  Here's the comment and my response: 

I think a lot of people have this gut reaction that a pregnant woman shouldn't be jumping, so I'll address this.  There are legitimate things to be concerned about with jarring exercises like jumping and running while pregnant, but "bashing [the baby's] heat (or head)" and causing brain damage is not one of them.  The baby is well protected by amniotic fluid in the uterus, and I cannot find a single (reliable or unreliable) source that says brain damage or anything like shaken baby syndrome can occur while in the womb.  But since pioneerworx is concerned about my baby's safety, I'll address some legitimate concerns about jumping while pregnant:
  • The uterus becomes heavy during pregnancy (baby + amniotic fluid + placenta) and puts pressure on the cervix.  Jumping and running can cause impact between the uterus and cervix, and could cause preterm labor.  Women vary in their ability to handle these activities during pregnancy, so the main thing is to listen to your body and STOP if it feels uncomfortable, especially if you experience any contractions.  The only risk to the baby here is being born too early, not physical injury from the impact of mom jumping.  As I mentioned in my last post, running is no longer comfortable for me, so I no longer run.  I still feel good doing box jumps and double unders, so I still do them.  If/when they become uncomfortable, I will stop.
  • During pregnancy, the placenta produces the horomone relaxin which causes the joints to loosen.  It also "relaxes" ligaments, allowing the uterus and pelvis to expand.  Good things for carrying and delivering a baby, but all joints and ligaments become looser, so pregnant women should be extra careful to avoid injury.  This is why advises not to squat below parallel and to be careful on box jumps (or do step ups).  Most women that were crossfitting before pregnancy will have strong muscles that can handle the shifting/loosening joints.  I personally have not yet noticed any difference because of this.  The risk here is injury to the mom, not the baby.
  • When anyone, pregnant or not, does box jumps, there is a risk of missing the box and falling.  Your center of gravity shifts during prenancy, although I have yet to experience difficulty balancing, I'm told it will happen.  But jumping does become more difficult as you gain weight (duh).  The risk of falling is the main reason I scaled down from 24" to 20" box jumps as early as I did.  I did miss one box jump in 12.3 (Justin was not happy with me about this), but I've never missed a box jump and come anywhere close to hitting my stomach on the box or actually falling to the ground.  I've never witnessed anyone else do this either.  I suppose it's a risk, but I see it as a minimal one. 
My main point: any source that talks about avoiding jumping/jarring exercises and activities while pregnant are NOT concerned about the baby shaking and getting brain damage.  Yes, the baby's brain is still developing -- that is a reason to get plenty of omega 3's, not a reason to stop doing box jumps.  There are legitimate reasons for me to stop doing box jumps at this point, but bashing my baby's head is not one of them.  

I'm not sure what type of injuries my critic is concerned about with push press, but in my opinion light to moderate weight push press (which is what 75# is for me) is one of the safest exercises to do while pregnant. 

Some references: (particularly the forum Q&A)

Obviously I don't agree with everything these sources say to avoid doing while pregnant, but the point is none of them say "jumping is bad because you are shaking the baby and can cause brain damage." 

72 days to go! 


  1. Thank you for this. I am 29 weeks and have been crossfiting 8 years now I'm sick of people telling me not to jump. My pregnancy so far sounds similar to yours I recently had to cut out running but DUs and box. Jumps are still fine minus the annoying people telling me not too. Thanks again for your blog!! I can't believe I just saw it 29 weeks and 2 days into my pregnancy.

  2. I don’t think there’s anything wrong about staying fit, or enrolling in some training while pregnant. In fact, there are certain routines that were developed just for the expecting mommies. So, as long as they are doing it in moderation, they’re good to go. Thanks for sharing!

    Sabrina Craig @ Medical Attorney