Photo from Mount Royal, Frisco, Colorado.

"Children are fascinated by the ordinary and can spend timeless moments watching sunlight play with dust. Their restlessness they learn from you. It is you who are thinking of there when you are here. It is you who thinks of then instead of now. Stop. Let your children become the teachers and you the student" - William Martin

Wednesday, 10 October 2007

Studies on running during pregnancy

Rather than continuing to ramble about how healthy and safe running is in pregnancy, I decided to see what studies have been done. A medline search for the keywords "running" and "pregnancy" yielded only 5 applicable studies/reports. I kept the editorials out. Here they are listed in reverse chronological order:

1. A study done in Korea just this year showed that rats that ran on a treadmill daily during pregnancy gave birth to "rat pups" with improved short-term memory compared with those "rat pups" whose mothers didn't run.

(Kim H, International Journal of Developmental Neuroscience. 25(4):243-9, 2007 Jun)

2. A German study from 2004 found that running women matched for age and weight to non-running women had improved placental blood flow and thus greater oxygen delivery to the baby. They speculate that this should improve feto-placental growth.

(Bergmann A, Placenta. 25(8-9):694-8, 2004 Sep-Oct)

3. A study done in 2002 in California showed that surveyed women who were more physically active had 30-50% lower risk for neural tube defects in their babies, even when they controlled for vitamin supplements they took. This study wasn't limited to running, though and included other forms of cardiovascular exercise.

(Carmichael SL, Maternal & Child Health Journal. 6(3):151-7, 2002 Sep)

4. A Canadian study from 2000 done in rats looked at 30 minutes a day on a treadmill 5 days a week vs a sedentary pregnancy. They found that the rat pups of the runners had a smaller body size, but larger brain to body ratio and normal organ to body ratios. They also found that there was less glycogen stored in the livers of the rat pups born to running mothers. The significance of less glycogen is not known. I also haven't seen this entire study yet (requested full article) and wonder if they didn't feed the same diet to the running and non-running rat mothers (certainly running mothers need to eat more!).

(Houghton PE, Canadian Journal of Applied Physiology. 25(6):443-52, 2000 Dec)

5. Finally a case report from 1999 of an elite marathon runner who ran intensively with twins up until 3 days prior to an elective c section at 36 weeks showed no adverse effects on maternal or fetal health. During pregnancy she did progressively slow the speed at which she ran and her heart rate continued to climb at subsequent weeks of pregnancy until delivery.

(Davies B, International Journal of Sports Medicine. 20(6):415-8, 1999 Aug)

Obviously not much research has been done. I also did a medline search for keywords "exercise" and "pregnancy" which brought up more studies that I'll have to report at a later date.

And in real life...

Here we are (SR and me) with helmet hair after a bike ride to the top of a mountain/hill looking out over the place we live. This is from last week and the golden days of fall. We hadn't ridden our bikes up there together before and I'm sure we had both been looking forward to the perfect day when we would. The day before this, there was a beautiful scent coming from the forest partially seen below, that lasted less than 24 hours and was gone by the time of this shot. How ephemeral and beautiful like life.

And we had just had sex in the golden warm sunlight coming through our window, feeling life as we'd always hoped it could feel, as if it were just the two of us on this vast enchanting planet. And then the great, sweaty bike ride.

But life moves too quickly. SR's parents came from their European land to Milwaukee, where my parents live, and everyone got to meet for the first time.

Here we are at the art museum where my mom works. As you can probably guess, my parents are the ones to the left.

Things have been really busy this past week with working and entertaining the house guests and keeping up the fanatical exercise routine, but I slept 9 1/2 hours last night, so things are back in order. Though it was difficult to sleep last night without SR here. I think we are both quite addicted to our nightly simultaneous orgasm. If someone had told me a year ago that that would be the norm in my life, I wouldn't have been able to believe it.

Anyway, though the running has gotten slightly slower this week, I am feeling quite good. All the muscle strains from the race are gone, as is the pubic symphysis ligament strain for which I believe SR's massage is to blame. So I'm continuing the daily 12 mile run plus bike and swim.

And I've finally resigned myself to the fact that I now have a 2 lb weight gain since the first OB appointment, making it 7lbs overall. Honestly, I hope to lose a pound in the next one or two weeks, just because running is slightly more cumbersome now, but it did seem inevitable that another pound would come at some point. Yes, readers, I am obsessive, but I'd never obsess over doing something if I felt it were any risk to the baby.

Below you can see the growing belly by the window of our cheap (see curtains) hotel

And finally, a recent favorite running song: Uhn Tiss Uhn Tiss Uhn Tiss by the Bloodhound Gang (I have to thank SR for introducing me to this one)


Run Forrest said...

"5. Finally a case report from 1999 of an elite marathon runner who ran intensively up until 3 days prior to an elective c section at 36 weeks showed no adverse effects on maternal or fetal health. During pregnancy she did progressively slow the speed at which she ran and her heart rate continued to climb at subsequent weeks of pregnancy until delivery."

Why did she have to have a c-section at 36 weeks? That's a month pre-term. Plus, thanks for the rat studies but you aren't a rat, you are a human. If your body is hurting during and after your run, it could telling you that it can't handle it.

coty said...

Hi, I have been interested in reading your progress with your running through pregnancy. Maybe you should start documenting yourself for other future expecting running mom's.

sea legs girl said...

Run Forrest,
Thanks for the comments. You do bring up some good points. As far as the c-section goes, it is within the standard of care to recommend a c-section to a woman with twins as there is a good chance one will be breach. The outcomes for "elective" c-section (as her's was... meaning she and her doctors chose this ahead of time) are much better than "urgent" or "emergent" (which often need to be performed in women who choose to deliver twins vaginally and this would have likely been the case had she waited much longer - hence the choice to deliver at 36 weeks as the lungs and baby are basically fully-developed at this time). So it was a sound medical decision and was not related to complications of the preognancy as far as I could tell.
As for the rat studies, it is very difficult to extrapolate what they mean as far as women are concerned. But I included them just to be complete (and because so few studies have been done). Also, the first study with the increased size of the hippocampus in the brain did correlate with the better blood flow seen in the human study, but I can't say much more than that. I couldn't really get much out of the second rat study.

P.S. Have you had experience with running in pregnancy? Just curious since your name is run forrest.

Thanks for your encouragement! I've been hoping to at least document the research I have done and add a little about my own experience, but I'm not sure what venue I should go for. Let me know if you have any ideas. I am quite happy to hear that there are other women out there interested in this topic!

olga said...

Listen to yourself, your own body and emotions.

Michelle said...

I think the reason Forrest was wondering about the last study you cited was because it doesn't say in the excerpt you provided that she had a multiple pregnancy. I would also have wondered why she had a pre-term elective c-section so early. And yes, I have had two babies born via c-section (the first an emergency one at 35 1/2-weeks, the second elective due to breech baby).

I guess as long as you listen to your body, then that's what matters.

Although I can't help but wonder why you try to keep justifying your exercising with all these studies. If you feel you are doing the right thing, what does it matter what anyone else thinks?

Take care and happy running.

sea legs girl said...

Thanks for the comments. I wanted to present all of the research, positive and negative that had been done about running in pregnancy, not to justify my running, but simply to present what, if anything, has been learned about this subject scientifically. If I had found multiple studies that showed adverse effects to the babies or mothers, I certainly would have thought twice about continuing to run. The reasons I run are many, but the biggest are it feels great and I think it is good for the health of me and the baby. I am now more convinced of this since I see some objective evidence of it. But I would have also written about the studies had they all been negative.
Sometimes listening to both scientific evidence and doing what feels right are equally important. I will address Olga's comment with this: many people listen to their emotions (or bodies) and their emotions tell them to sit around and eat donuts all day. So we need to combine doing what we have learned is right scientifically with what our bodies seem to be telling us. And we should not ignore either our bodies or the facts. Had I listened to just my body back in high school, I would have continually found a reason to NOT run, because it's hard. But you push yourself because you know it will be worth it.
And Michelle, I will have to look back at the article (work has been busy) to see if they specify the reason she chose to have a c-section. But I repeat 36 weeks is not early to have an elective c-section, to avoid exactly what happened to you: an emergency c-section (and I hope everything turned out alright!). That's why electives are done before term, but when the baby is basically fully developed.

sea legs girl said...

Oops... I guess I didn't even mention that she was expecting twins when I wrote about the case study of the elite marathoner. I'll have to edit the post. Sorry about the confusion!

Barbara said...

Doctor's don't like to schedule c-sections before 38-39 weeks, and that is because a baby's lungs are not always fully developed before then. Performing an elective c-section at 36 weeks simply because a mother is carrying twins isn't routinely safe unless there are complications necessitating one, here's a study for you. It advises delivering twins only at 38 completed weeks' gestation or later to avoid neonatal complications:

All my baby's were born via c-section at 38 weeks or slightly thereafter. (With the first my water broke, and at over 9 lbs he was still stuck after 24 hours.) I had big babies. I exercised during my pregnancies, but I did listen carefully to my body, and didn't push myself too hard. It just isn't worth the risk. Any kind of pain happens for a reason. SeaLegsGirl, I am not sure you can really compare yourself to the women in the running studies, because you run more intensively than "30 minutes a day on a treadmill 5 days a week". I applaud you keeping in shape, that's awesome! But just listen to your body, and don't overdo it.

sea legs girl said...

Hi Barbara,
Thanks for the link to the study! Yeah, I don't know why her and her doctors chose to have the c-section, but since it was elective and they explicitly said there were no complications, that is all I can report. As for the maturity of the lungs, any baby born by elective c-section before 38-39 weeks gets their lung maturity assessed before the c-section proceeds by one of two tests:(1) biochemical tests measure the concentration of particular components of pulmonary surfactant and (2) biophysical tests evaluate the surface-active effects of these phospholipids. So they most certainly knew the baby's lungs were mature before the delivery.
You're right that I run more than the women (and rats) in any of these studies. But I couldn't find any studies that had been done on women who run as much as I do, so I simply reported all studies I could find on running in pregnancy. There is, of course, a limit to how much any study can apply to an individual.
Congrats to you, too, on keeping up the exercise during pregancy! I'm not sure where you got the idea that I've been in pain or I'm not listening to my body. I had a slight ligament pull at my pubic symphysis (could easily tell the pain was not internal) over a week ago, but that resolved after 2 days. As of right now, I can honestly say I have never felt so good! I'm just running a bit slower these days :), and I'm perfectly okay with that.

Michelle said...

Thanks for the clarification on that study. :-)

My emergency c-section was a nightmare (I will spare the details), but in the end (after 20 days in the NICU, but not due to breathing issues, thank goodness) my wonderful daughter got to come home. She is almost four now and bossy as they come. My scheduled c-section with my boy was a breeze in comparison!!

I just have to add I wish I could run 12 miles a day! I don't know if that will ever be in the cards for me, though. I am just not built like a gazelle. ;-)

gnome517 said...

I personally worry about your preoccupation with your weight and your stated desire to lose weight. THat's not really what your body needs right now. Your baby will get what he needs, but he may do so by taking from you since you may not be providing all the nutrition your body needs to provide for both.

Gretchen said...

Hi there Sea Legs

I'm happy to read your page. I am a moderate runner and ran four marathons last year. I ran about 20-30 miles a week then, and in my pregnancy I've cut to about 10 - 16 miles a week. I ran a half marathon yesterday 40 minutes slower than my best time. I haven't gained any weight at all in my second trimester (I gained 2 in the first) but I eat like a horse. Everything I have read has only said running at a moderate pace is beneficial to the baby and mother, and my doctor tells me to exercise 5-6X a week, but of course I still worry. Seeing your healthy little one is reassuring - thank you.

harry said...

There are various online sources to provide you informative details on FDA approved weight loss pills as well as information on pills and tablets available in the pharmaceutical market that are capable of successfully relieving you from the grip of erectile dysfunction and depression. But the online pill destination is somewhat unique as it makes a whole array of information available to you, including details on the highly popular pills and tablets, testimonials as well as news on the latest tidbits of the pharmaceutical market. Log in to the website and get hold of relevant pill-care details.

Jin Yi said...

Hello. I was looking though the web to see if I could find any info on when you should STOP running. All of you mention "listening to your body" but I'm not sure how to know when the pain or the breathlessness is bad or still ok. I am an avid runner and have cut down my running quite a lot from 6-14 miles a day to doing just 3-6 miles a day. Which I am completely happy with - better than no running! Once in a while I'll feel some tightness and slight pain in my lower tummy and for sure my breathing has gotten a lot harder but to me this is not a reason to stop running. What kind of pain should I be feeling to stop running? Also, do you recommend getting some type of support for your tummy to minimize all that up and down movement? Really curious because I'd like to continue running until the day I deliver. It just keeps me sane. Thanks for all the GREAT info. I love the studies. I couldn't care less if they were done on rats or humans. Any positive info. is encouraging enough for me.

Erin S. said...

I am so happy to have found your blog! I am also an avid runner (pre-pregnancy, I averaged about 60 miles per week). I am pregnant with my first child (19 weeks along) and have continued running (up to 6 miles at a time, up to 9 miles per day). I have slowed down significantly - am now running 10 minute miles. I have felt fine, but have read some things recently to make me question if I should slow down even more, maybe even start WALKING....even thought the thought just about kills me. My concern is this: I've read and even my doctor has given me the 140 HR guideline. I'm pretty sure that my HR is going above 140, but like I said, I FEEL FINE! Any comments on this guideline?

sea legs girl said...

Erin S. Wow you managed to find an OLD blog post! 4 years old. Hard to believe. Congrats on your pregnancy. Glad you are still running and no reason not to as long as it keeps making you happy :). I have seen no evidence that a pregnant woman's pulse should remain under 140 during exercise (that is really low. How could one even get a workout at such a low pulse if one is say 20 years old? Even at 30, that is not very strenuous). Doctors are, as far as I have read, getting away from recommending women stay under a certain pulse. It is much better to exercise according to how you feel and not get stressed by trying to measure your pulse. I have now gone 2 pregnancies with lots of exercise and no pulse measurments. I actually only recently starting measuring my pulse while spinning and at times get it up in the 160's (and I'm 34 weeks along), though it is the fact that I start to feel crappy that makes me slow down. Good luck. Feel free also to email me at!