The problem is that reducing risk is out of the midwives hands. Really, the answer seems to be that you have to somehow convince the woman to make the dietary and lifestyle changes to stay within the Institute of Medicine (IOM) weight gain guidelines.
Coming to Terms with the Guidelines
I have to tell you, when I first heard about the guideline changes I was angry and convinced the science had to be bad. How can the IOM recommend that women gain less weight than the baby and placenta and fluid weigh. This is essentially recommending that women diet during pregnancy and I was raised in the natural birth world where pregnant women don’t diet. This had to be a mistake.
So I listened to lectures about the key research that lead to the guideline changes. The data was compelling – mothers and babies were much healthier when they could stay within the guidelines. But I still was not convinced. And then I learned something that touched my nutrition nerve, and it was like an arrow straight into my heart.
One midwife researcher explained that we often forget just how many calories it takes an obese pregnant woman to maintain her body weight. Most women seem to try to make dietary improvements when they are pregnant, so a woman may be eating the healthiest diet she’s ever had. She may not be able to eat enough calories to prevent losing weight.
It was like a light bulb went off in my head. These guidelines were not about restricting women to a diet death sentence. These guidelines were about what most obese women could expect to happen if they made the changes they needed to reduce all the risks of obesity – not just the pregnancy risks. And it was at a time they were most interested and open to making changes. Would it be hard? Yes, but if they were successful they wouldn’t only improve the chances of having a healthy pregnancy, she would improve her chances of having a healthy life.
Evidence for the Guidelines
A UK review of the effectiveness of interventions on obstetric outcomes was published in 2012. I had seen the data on the improved outcomes, but honestly I still had doubts. After all, I keep reading on blogs that weight loss does not make any improvement during pregnancy. So I was really interested in what this ridiculously thorough literature review would say.
Dietary interventions do lead to a reduction in weight gain for the mother – about 3.5 kg compared to the control group. That is about 7 – 7.5 pounds, enough to make a significant reduction in the number of women who exceeded the IOM recommendations for weight gain.
And it turns out that dietary interventions also reduced the number of large for gestational age babies without increasing the incidence of low-birthweight or small for gestational age babies. This was amazing, because this was exactly what I had been taught to be afraid of – dietary interventions lead to poor growth in the baby. It turns out the science doesn’t actually support that idea.
So weight gain was reduced. But did that make any difference in the risks? Actually yes. There is a 25% reduction in the rate of preeclampsia. When the weight management intervention was a dietary intervention rather than an exercise intervention, the rate of pre-eclampsia was up to 50% lower in the women using the dietary intervention than the control group. Up to an 80% reduction in the rate of shoulder dystocia.
It gets even better. Dietary weight management reduced the rate of preterm births by 40%. The rate of gestational hypertension by 30%. They also reduced gestation diabetes by 50% – but statistically this number couldn’t be considered significant.
All these benefits for the mother, and there was no difference in any of the measures of neonatal health. This unfortunately means the weight management interventions didn’t lower the rate of stillbirths or perinatal deaths associated with obesity. And, the weight management interventions didn’t reduce the rate of induction or cesarean surgery.
So the next question is, “Now that we know, what should a midwife do?” We will discuss this question tomorrow.