Infants born to women using commonly prescribed antidepressants during the first three months of their pregnancies are imposed to an increased risk of serious birth defects, though the danger remains tiny, according to a couple of newly published studies.

The publication in the New England Journal of Medicine found a higher risk of developmental problems influencing the intestines, brain and skull. Although life-threatening, all of the defects are rarely happening and normally happen in no more than one in 2,500 births.

"The take-home message is that we are talking about very small risks," reported UC San Diego epidemiologist Christina Chambers, who has studied the effects of antidepressants but did not take part in the new researches.

The studies are the most recent to raise worries about the effects of antidepressants on fetuses. Babies born to women on antidepressants were shown to experience signs of withdrawal, including tremors and sleep disturbances, during the first days of their life.

Others studies showed a linkage between a mother's antidepressant use later in pregnancy to an increased risk of lung problems in newborns. A couple of reports have tied the drug Paxil, particularly, to a higher rate of congenital heart malformation. The drug carries a warning about heart defects.

The recent studies were the largest yet to analyze the relation existing between antidepressants and possible birth defects.