A new study has found that expectant mothers who dealt with the strain during their pregnancy had children who were at elevated risk for abnormal health conditions at birth. The strain is usually one of a hurricane or a tropical storm passing by during the pregnancy.
The study led by a Princeton University researcher 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 faeces - 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.
One potential cause of the health problems found in the study is an increase in stress hormones caused by the storm, which occurred in what is known as the neuroendocrine pathway.
"I think the takeaway finding is that it's worth doing more focused research on those pathways and looking for more subtle effects on the fetus than just looking at birth weight and preterm delivery," Currie said.
"And it would be really great if we could follow over time and see what happens to children who are affected by these types of events," she added.
The study has been described in a working paper circulated in May by the National Bureau of Economic Research.