Friday, October 28, 2011

Restricting Prenatal Weight Gain in Women of Size: Adverse Side Effects

Here's another study questioning whether rigid weight-gain restrictions in "obese" women are wise.  

We've talked about this extensively before.  But given how often care providers tout this as a way to improve outcomes in women of size, it bears frequent repetition.

In this study, the lower Cedergren weight gain criteria for obese women (less than 13 lbs.) resulted in slightly lower cesarean rates and definitely less macrosomia than the IOM guidelines.

However, it also resulted in an increase in preterm births, low birth weight babies, and NICU admissions.

Many providers mean well when they advise women of size to gain less weight in pregnancy. The question is, are we harming more than we are helping?

When restrictions are too draconian, I think the balance definitely falls to harm.

Discuss good nutrition and reasonable intake? Absolutely.  Have rigid weight gain goals that require significant restriction?  Not a good idea.

How about we emphasize excellent nutrition and trust the woman's body to gain what it needs?

Am J Perinatol. 2010 May;27(5):415-20. Obstetric outcomes in normal weight and obese women in relation to gestational weight gain: comparison between Institute of Medicine guidelines and Cedergren criteria. Potti S, Sliwinski CS, Jain NJ, Dandolu V.  PMID: 20013574 
We compared obstetric outcomes based on gestational weight gain in normal-weight and obese women using traditional Institute of Medicine (IOM) guidelines and newly recommended Cedergren criteria. Using the New Jersey Pregnancy Risk Assessment Monitoring System (PRAMS) database and electronic birth records, perinatal outcomes were analyzed to estimate the independent effects of prepregnancy body mass index (BMI) and gestational weight gain by IOM versus Cedergren criteria. Of 9125 subjects in PRAMS database from 2002 to 2006, 53.7% had normal BMI, 12.3% were overweight, 18.2% were obese, and the rest were underweight. 
Among normal-weight mothers, when compared with the IOM guidelines, macrosomia (6.45% versus 4.27%) and cesarean delivery rates (30.42% versus 29.83%) were lower using Cedergren criteria but the rates of preterm delivery (5.06% versus 9.44%), low birth weight (0.38% versus 2.42%), and neonatal intensive care unit (NICU) admissions (7.02% versus 10.86%) were higher with the Cedergren criteria.  
Similarly, among obese patients, when compared with IOM guidelines, macrosomia (10.79% versus 5.47%) and cesarean delivery rates (43.95% versus 40.71%) were lower using Cedergren criteria but the rates of preterm delivery (6.83% versus 8.32%), low birth weight (0.87% versus 1.88%), and NICU admissions (8.92% versus 13.78%) were higher with the Cedergren criteria.  
Based on our results, ideal gestational weight gain is presumably somewhere between the IOM and Cedergren's guidelines.


Elizabeth said...

You may not know, but did this study take into account whether women actively tried to limit weight gain or if it just happened? Though since it increased pre-term birth, low birth weight, and NICU admissions, I'm assuming the former. I know for myself (pre-pregnancy weight of 292) I lost down to 282 during the first trimester, then gained up to a high of 302, and I weighed 299.5 at the hospital. So if we're talking net gain, I met the Cedergren criteria with a net gain of 8 lbs, but I mostly ate what I wanted when I wanted and that was what my body did. I could just as easily have gained 20 or 30lbs net. I know you've mentioned before that there's a difference between low weight gain with no effort and restrictive eating, but I do wonder if not controlling for that differences might have skewed their data.

Well-Rounded Mama said...

Yes, I wondered the same thing.

I'm like you (and many other women of size) and lose a bit at first, then regained by the end. My total net gain was close to 5 lbs. in each of my pregnancies. So I too met the Cedergren criteria.

I don't think this is harmful when the body naturally does it. Some of our bodies just respond to the increased metabolism of pregnancy that way. I think outcomes in those whose bodies just do it coincidentally are generally good as long as their nutrition is good.

But to generalize and say that ALL women of size should gain in that amount, and should restrict intake in order for them to meet that goal, that's a totally different thing in my mind. I don't think the outcomes would be nearly so good if that happens.

Anonymous said...

This is a very pertinent issue right now in my life as I am pregnant with #4. I started this pregnancy at about 285 and I am now down to 267. I have been watching my carb intake as I developed type II after delivering a 12lber (and I didn't have diagnosed GD...passed the 3hour). Hindsight tells me I had some issues going on in pregnancy #3. THe weight loss is typical for me though, as with all 4 pregnancies I lost a fair amount of weight and only net-gained around 8-10 lbs each time.

I just took the 3hour GTT at 10 weeks, but am managing to keep my numbers under control with diet and glucophage. I am guessing insulin is in my future, since my 1 and 2 hour numbers were elevated (well, according to my glucometer).

I think I would rather take some insulin instead of starving myself and really restricting carbs. I am not indulging in sweets, but I was having horrible headaches and feeling crappy when I was super lowcarbing. Plus, what kind of nutrients am I missing out on for the baby? Still researching on this one, though.

Great blog!

KaralynZ said...

I was anxious about gaining weight during pregnancy since I was already considered overweight but my midwives were not worried about it. And since they worked with me on making sure my nutrition was good, and since I was able to continue to exercise pretty much up to the end, I relaxed about it too. I ended up gaining just over 40 lbs and all but 10 of it was off within 6 weeks.

Anonymous said...

My midwife is fantastic and advocates the Brewers diet for all of her patients. I have had a hard time eating everything on the plan pretty consistently-its a lot of protein. But I have had no issues-weighed 240 to start at 5'7. Have gained about 23 at 7 months. She thinks that's just fine as long as I follow the plan. I am 40 and she thinks I am on track for a birth center birth. No interventions! I have to say its a refreshing change from my regular ob-gyns office. Protein was always a big deal for my weight and general well being before the baby, and that hasn't changed as pregnant. Focusinng on a healthy diet instead of a number cannot be understated.