Researchers from Princeton University found that stress during pregnancy leaves a baby more at risk of conditions such as breathing syndrome "meconium aspiration" and being placed on a ventilator for the first half hour of its life.
Meconium aspiration, usually a sign of foetal distress, occurs after babies breathe in a mixture of meconium, or early faeces, and amniotic fluid around the time of delivery.
In the study, the researchers analysed both birth records and meteorological information to find children born in Texas between 1996 and 2008 whose mothers were in the path of a major tropical storm or hurricane during pregnancy.
The results, published in the National Bureau of Economic Research, showed women living within 30km of a hurricane's path during their third trimester were 60 per cent more likely to have a baby with abnormal conditions.
These conditions included being on a ventilator for more than half an hour or experiencing meconium aspiration.
An increased risk was also found following exposure to weather-related stress in the first trimester, while evidence was less clear for exposure in the second trimester.
More From This Section
The researchers believe the results could be down to an increase in stress hormones caused by the storm, which occurred in what is known as the neuroendocrine pathway.
"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," Prof Janet Currie, who led the study, was quoted as saying by the Daily Mail.
"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," Prof 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. 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 foetus than just looking at birth weight and preterm delivery," she added.