Stress and Pregnancy

Photo: Pregnant Woman

© Hemera

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 kilometres 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.

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.

"I think there's every reason to believe that if you have a better measure of child health — like you knew this child was having breathing problems at birth — that might be a stronger predictor of longer-term outcomes," Currie said. "There's a lot of interest in this whole area of how things that happen very early in life can affect future outcomes."

Previous research into the impact of similar types of stress has found changes in length of gestation and birth weight, but the new study didn't find a significant effect on those measures, Currie said. One explanation for the difference is that the new study utilized data that allowed the researchers to control for changes in the population of an area around the time of a storm that could have affected the previous findings. Earlier research hasn't been able to account for the way the population of an area changes around the time of a stressful event — with people of certain demographic groups more likely than others to move away or stay nearby.; Source: Princeton University