If you’re pregnant and in the path of a major storm, it may be time to skip town –- or at least enroll in mediation classes.

Compared to gestating mothers who lived through calm skies, moms who lived within 30 kilometers (18.6 miles) of a hurricane during their pregnancies were 30 percent more likely to end up having complications during labor or delivery, found a new study. They were 60 percent more likely to end up giving birth to newborns in distress.

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More post-storm babies, for example, experienced meconium aspiration, which happens when a baby breathes in a mixture of amniotic fluid and early feces during delivery. Post-storm newborns were also more likely to have breathing problems and spend more than 30 minutes on a ventilator after birth.

Babies exposed to storms during the third trimester were more likely to end up breech instead of head-down at the time of birth. And babies exposed during the second trimester were more likely to end up being born by C-section.

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Storms did not appear to affect birth weight. Nor did they cause women to go into labor any earlier.

"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 Janet Currie, a professor of economics and public affairs at Princeton University, in a press release. “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."

Plenty of research has shown that traumatic events can have negative effects on pregnancies, leading to miscarriages or to babies born too early or too small. But most of those studies fail to separate out the effects of stress from the effects of whatever else is happening at the team, leading to confusion about what causes what.

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For the new study, which was released by the National Bureau of Economic Research, Currie and colleagues looked back at eight hurricanes and tropical storms that hit Texas between 1996 and 2008. All of the storms, including Allison and Ike, caused more than $10 million in damage. The researchers used Texas birth records to compare where mom’s lived with the outcomes of births and their timing in comparison to storm strikes.

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To explain the link between hurricane encounters and birth problems, the researchers were able to rule out storm-related complications, including injuries, crowded shelters, exposure to environmental toxins, and lack of clean water, safe food, or healthcare. That left stress as the likely cause of labor and delivery problems.

If doctors know that a woman dealt with the ordeal of a major hurricane during her pregnancy, the authors say, they may be better prepared to help her and her newborn thrive after birth.

Credit: Corbis