Newborns don’t face significantly increased risk of birth defects from antidepressants that are taken by moms early in their pregnancy, according to a pair of studies in The New England Journal of Medicine. The overall risk of giving birth to a child with a defect increased by less than 1 percent in women on SSRI drugs, which include Prozac, Paxil, Celexa and Zoloft. Here’s one study, and here’s the other.*

The findings have widespread implications, because depressed moms who can’t care for their newborns pose a danger. But Glaxo’s Paxil already carries a warning of possible heart defects in newborns, prompting questions about the entire class of drugs. As a result, some docs say the studies should allay those concerns.

“If everyone decides that treatment for depression is appropriate and needed during pregnancy, the overall message from this is relatively reassuring,” Michael Greene, director of obstetrics at Massachusetts General Hospital in Boston, tells Bloomberg News. He wrote an accompanying editorial that the link between SSRIs and defects appears “small in terms of absolute risks.”

“Yeah, there’s a risk,” Susan Ramin, obstetrics chairman at the University of Texas Medical School in Houston, tells the Associated Press, “but the risk overall is probably pretty small.”

The two studies - one from the federal Centers for Disease Control and the other from Boston University - use more cases of birth defects than previous research to consider links between defects and and SSRIs. The BU study was funded partly by the National Institutes of Health and Glaxo.

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Together, the two studies looked at 19,471 newborns with birth defects and 9,952 without them. Then they considered what SSRIs the mothers in both groups took during the first three months of pregnancy and mapped the patterns of birth defects, the AP reports.

Neither study was able to tie SSRIs as a group to either heart defects or most other defects. That reassurance is especially welcome because depressed women fret even more than other mothers about the health of their newborns, says Stephan Quentzel, a psychiatrist who treats pregnant women at Beth Israel Medical Center in New York City.

Also, a mother’s untreated depression can lead to poor care or turmoil at home, a weaker maternal bond, and other problems for a newborn. “The fetus and the newborn are almost always worse off if the mom is depressed than if … exposed to the vast majority of antidepressants,” Quentzel says.

However, doctors and mothers have been very wary about medications and birth defects since Europe’s thalidomide scandal of deformed babies in the 1960s. Defects from all causes are expected in about 3 percent of births, enough to make many mothers nervous.

The concern about SSRIs grew out of Glaxo’s own alert in 2005 about possible heart defects in newborns whose mothers took Paxil early in pregnancy. The FDA added its own warning. Last year, a separate study linked SSRIs taken late in pregnancy to a lung disorder in newborns.

The latest studies do not consider that disorder, known as persistent pulmonary hypertension. But they suggest that the risk of other defects from an SSRI - even if confirmed - would add only a fraction of 1 percent to the overall danger, researchers said.

Paxil did appear to triple the risk of a defect in blood flow from the heart, both studies found. But that additional danger would still be modest, experts say.

The studies further hinted at possible ties between other SSRIs and a handful of other defects, but researchers said the numbers of newborns with specific defects were too small to draw strong conclusions.

“Based on these studies, it’s correct to say: no major risk,” Carol Louik, a public health expert who led the Boston study, tells the AP. “I wouldn’t say, ‘No risk.’”