Weight Gain During Pregnancy: Q & A with Naomi Stotland, MD

Putting on a few extra pounds during pregnancy has been thought to be a normal and healthy part of the gestational process. But what happens when a woman gains too much weight, or too little? According to data published this month in Obstetrics & Gynecology, babies of women who gain more than the upper limit of Institute of Medicine (IOM)-recommended guidelines during their pregnancy may be subject to a myriad of adverse conditions immediately following birth. Translated, this means that a woman at a normal weight based on body mass index (BMI) standards has a cutoff of gaining up to 35 pounds, or she can be at risk for adverse neonatal outcomes. Normal-weight women who gain less than 15 pounds are also found to be at risk. Lead author Naomi Stotland, MD, assistant adjunct professor in the UCSF Department of Obstetrics, Gynecology and Reproductive Sciences, took a moment to comment on the findings. Q. We know that excessive weight gain has been shown to have adverse effects for mothers. How is this study different? A. We focused on specific outcomes or illnesses of the infant immediately after birth, while many of the previous studies looked primarily at birthweight. We looked at some of the conditions that occur and at the relationship between occurrence and weight gained during pregnancy. Among the conditions that we charted were birth trauma, neonatal infection such as neonatal sepsis or pneumonia, low blood oxygen, five-minute Apgar score less than 7, seizures, hypoglycemia, polycythemia, meconium respiratory distress, jaundice, anemia, aspiration syndrome and size of infant for gestational age. In circumstances where low weight gain occurred, we also ascertained what, if any, of these same conditions appeared. Q. What were some of the conclusions, as they relate to specific outcomes? A. For women who had high weight gain, there were higher rates of babies with a five-minute Apgar score less than 7. This is a test that tells how well the newborn adapts to the environment outside the womb; an 8 to 10 score in this test indicates a healthy baby. We also saw higher rates of need for assisted ventilation, larger-sized infants, neonatal infections, hypoglycemia, seizure, and special care nursery admission and longer hospital stays. Except for lower birthweights, we didn't see increased risks associated with overall weight gain below the IOM guidelines. But when we looked at women with very low gain - less than 15 pounds - rates of these complications were increased, as well. Q. What about obese women who gain excessive weight while pregnant? A. In previous research, we had found that women classified as overweight or obese, according to their pre-pregnancy BMI, were more likely to gain above the IOM guidelines. In fact, women who gained above the IOM guidelines were also more likely to undergo cesarean delivery and have infants with higher birthweights. Since we were looking at fairly uncommon complications of the newborn, we didn't have enough subjects to look for differences between obese women and normal-weight women with regard to the findings of our study. Our cohort was very large: The study consisted of reviewing data from 20,465 births at UCSF between 1980 and 2001. Of these, over 43 percent gained an amount that was above the IOM-recommended guidelines. Even though 36.6 percent were within the IOM guidelines, over 20 percent were below. Of these figures, 29 percent of the 43 percent above the guidelines gained more than 40 pounds, and 4.8 percent gained less than seven pounds. Q. Should pregnant women now be more conscientious when it comes to staying within certain weight ranges? A. Many pregnant women gain too much weight. Looking at this from a population standpoint, women who gain within the ranges are more likely to have healthy, full-term babies. While there are risks associated with excessive weight gain, many women with high weight gain have healthy babies and do just fine. We don't know if the relationship between high weight gain and infant complications is cause and effect, or related to some other unmeasured factor. However, we also know that women who gain too much weight are more likely to retain this weight postpartum, and that can lead to adverse health effects for mothers long term. Q. What do we learn from this? A. Pregnancy is a great time to work on healthy habits because there is an extra incentive - to have a healthy baby. Women should perhaps not fixate on the number of pounds, but concentrate on healthy lifestyle changes.

"Gestational Weight Gain and Adverse Neonatal Outcome Among Term Infants" Naomi E. Stotland, MD, Yvonne W. Cheng, MD, MPH, Linda M. Hopkins, MD and Aaron B. Caughey, MD, MPP Obstetrics & Gynecology 2006;108:635-643 Abstract | Full Text | Full Text (PDF)