Photo from Mount Royal, Frisco, Colorado.

"That is happiness; to be disolved into something complete and great. When it comes to one, it comes as naturally as sleep." - Willa Cather

Friday, 10 December 2010

The most notable studies on running in pregnancy

In light of Steph's question about studies on distance running in pregnancy, I thought I'd make a list of all the studies that came to mind, which I have read over the past few years, that deal with health and safety of running/exercising in pregnancy. For those of you who have been reading for years, this isn't the first time I've mentioned most them.

Bear in mind that this list is no substitute for good clinical judgement and there ARE contraindications to running while pregnancy (but great debate exists around what exactly those contraindications should be).

Clapp 1989 - women running 19-88 km/week or aerobics three or more times a week.

Spontaneous abortion (miscarriage)
controls: 25%
aerobic dancers: 16.5%
runners: 16%

Hall & Kauffman 1987

Strength training and c-section rate
control: 28%
low intensity: 24%
medium intensity: 19%
high intensity: 6%
(I know. It's not running - but wow - ALMOST as good as running [see below]!)

Clapp 1990

running 14-68 km/week and/or aerobics 3-11 times per week (case control study; controls were equal in education and age, etc)

c-section rate

controls: 30%
runners: 5%

length of labor

controls: 390 minutes
runners: 260 minutes

meconium (sign of baby distress) when water breaks

controls 25%
runners: 14%

abnormal heart rhythm in baby during labor

controls: 25%
runners: 14%

Long-term baby outcomes (baby now 5 years old; same running women and controls)

-children of runners significantly leaner and more active
-children of runners significantly "much" higher IQ and oral language skills

Sørensen et al 2003

Pre-ecclampsia rates

controls - control rate
physically active: 35% relative risk reduction
physically active more than 6 hours per week: 69% relative risk reduction

Juhl 2007 Danish National birth cohort:

20% reduced chance of preterm birth among women who exercise > 5 hours per week

This last study is the one I am applying to get permission to analyze specifically for women who run more than 5 hours a week.

P.S. Steph - I'm not trying to give you specific advice, but you mentioned wanting to see studies, so I hope this might be some of what you're looking for.

In other news, The Lorax has chickenpox. He seems completely unbothered by it. I don't think they itch him at all. Happily I've had it, otherwise I'd have yet another pregnancy worry to dwell on.

Speaking of which, I gave myself an ultrasound in the ophthalmology dept. today, just to make sure my pregnancy was intrauterine. The tiny eye probe went just deep enough so I could identify the anterior side of the uterus. I found what might be the gestational sac on the left, but it might have been bowel. There is a reason people go to ultrasonographers, I guess. In Denmark, you have to wait until week 12 to get an ultrasound, so I've got a while - but I'll probably know if it's ectopic before then anyway.


Stefanie Schocke said...

"I gave myself an ultrasound today"...had to laugh at that :)

Okay...what about women who run 5 or 6 hours a week, but at a slow pace. For example, are running 5 miles a day, but at a 12 minute mile.

sea legs girl said...

Stafanie, women who do that would still fit into Clapp's, and I think all the studies' (except the strength training) exercise/run group OR intense exercise group. So they'd get all of the benefits of exercising that are discussed here. I don't think any of the studies specified that you had to run faster than a certain pace.

The woman you describe sounds a lot like me the last month I was pregnant with The Lorax. Though I added swimming, spinning and core exercise to it.

Glaven Q. Heisenberg said...

The first article sounds interesting. Where can I get the Clapp?

Hahahaha! Don't bother answering! Now that I've said that, the article no longer interests me.

But truth is, I am carrying a bit of a beer baby in my belly. I'm going to name him "Gadiater" after the word verification word you blog just gave me.

Is that Danish for "Gladiator"? Or "gadfly"?

(If it's a girl I'm going to name it "Rutabaga", because then her significant other will never have to attend lame Xmas parties in Minnesota.

sea legs girl said...


Why doesn't it surprise me that you'd be interested in getting "the Clapp"? I think you know how you can get it - in fact you have probably "borrowed" it from women before. :)

SteveQ said...

I got chickenpox at 17, missing my high school prom, the state championship track meet and the first "last-ever" concert by the Who.

Now I'm wondering if the vaccine helps prevent shingles.

sea legs girl said...


My reason for not rushing off and vaccinating The Lorax was that I am nearly 100% sure it will not prevent shingles. (If you look it up, they will say the verdict is still out). The reason it probably won't protect is it is a live (attenuated) virus and if it gets in the body, it will set up shop in the nerves, where it likes to live. Years later, it will have the chance to come out again just like it does if you've had actual chickenpox. It is just a matter of the immune system being compromised later down the road and the virus coming out again. In theory, Shingles may be MORE of a risk after you have the vaccine, because you might not reach the same level of immunity, so it might take less for a reactivation.

Did that make any sense?