Study offers new insights into the effects of stress on pregnancy

Expectant mothers who dealt with the strain of a hurricane or major tropical storm passing nearby during their pregnancy had children who were at elevated risk for abnormal health conditions at birth, according to a study led by a Princeton University researcher that offers new insights into the effects of stress on pregnancy.

The study used birth records from Texas and meteorological information to identify children born in the state between 1996 and 2008 whose mothers were in the path of a major tropical storm or hurricane during pregnancy. The children's health at birth was compared with that of siblings whose gestation didn't coincide with a major weather event.

The study found that mothers living within 30 kilometers of a hurricane's path during their third trimester were 60 percent more likely to have a newborn with abnormal conditions, which are detailed on birth records. Those conditions included being on a ventilator for more than 30 minutes or experiencing meconium aspiration, which occurs when a newborn breathes in a mixture of meconium - or early feces - and amniotic fluid around the time of delivery. Increased risk was also found following exposure to weather-related stressors in the first trimester, while evidence was less clear for exposure in the second trimester. The researchers were able to isolate the impact of stress caused by the storm from other factors, such as changes in the availability of health care in a storm's aftermath.

The study breaks ground by honing in on new — and potentially better — ways to measure the impact of prebirth stress on newborns and opens avenues for further research into the potential impact on such children's later development, said lead researcher Janet Currie, Princeton's Henry Putnam Professor of Economics and Public Affairs at the Woodrow Wilson School of Public and International Affairs and director of the Center for Health and Wellbeing.

"Probably the most important finding of our study is that it does seem like being subjected to stress in pregnancy has some negative effect on the baby, but that the effect is more subtle than some of the previous studies have suggested," said Currie, who conducted the study along with Maya Rossin-Slater, a doctoral candidate in the Department of Economics at Columbia University.

Anna Aizer, associate professor of economics and public policy at Brown University who wasn't involved in the study, said the research "really raises the bar in terms of identification of the effect of stressful events in-utero on birth outcomes."

"Previous work has not really been able to isolate the effect as well as Currie and Rossin-Slater have," said Aizer, whose research focuses on issues related to children's well-being.

Meconium aspiration — usually a sign of fetal distress — and other respiratory problems that necessitate a baby being placed on a ventilator can generally be treated successfully, but the study offers new paths for future research about the long-term health of children born in the wake of stressful events such as hurricanes.