Patients with a history of preterm labor and delivery do not benefit from controlled weight gain and dietary changes, according to research completed at the University of Rochester Medical Center. After reviewing pregnancy and birth records for 166 women who delivered their first and second pregnancy at the medical center, there was no indication that controlling diet and weight changes made a significant impact on pregnancy outcome.

The study did not necessarily focus on the impact of excessive weight gain; rather, researchers wanted to assess whether or not healthy weight gain could be used to protect women with a history of premature delivery against future premature delivery. According to study author David Hackney MD, “Usually, weight gain and being overweight or obese is protective against spontaneous preterm birth. In fact, the risk of unexpected labor and delivery is 20-percent lower in obese than non-obese women.” Hackney went on to explain that researchers participating in this study were looking for a negative correlation between weight gain and preterm labor; specifically, an increased rate of preterm delivery when pregnant women gained less weight during the second pregnancy. No such correlation presented in the medical records, so women who gained less weight, average weight, and more weight during the second pregnancy had the same increased risk of premature delivery.

Weight gain was recorded during the first and second trimester. Third-trimester weight gain was not used for the study because many of the participants delivered before the third trimester. Delivery records for first and second pregnancies were collected from patients delivering at the medical center between 2004 and 2010. Age, BMI (pre-pregnancy) and tobacco use were taken into consideration.

Patients who delivered the second baby full term were older than women who experienced a second preterm labor. About 29-percent of women in the study delivered the second pregnancy preterm.

Researchers noted that this study included weight gain during the first pregnancy, between pregnancies, and during the second pregnancy – broadening the scope of the study.

Removing weight gain as a possible controlling factor in the prevention of future preterm delivery may help obstetricians focus care on factors that may impact preterm delivery like tobacco use, alcohol use, and illegal drug use.

Source: David Hackney MD, Danielle Durie MD, Radhika Tirumala MD. University of Rochester Medical Center. (Presented at the annual meeting of the Society Maternal-Fetal Medicine.) February 2012.