The study offers new information but no clear answers for expectant mothers who must balance the risk of medications harming the fetus against the danger of untreated depression.
"It's important that patients not assume that the hormones of pregnancy are going to protect them from the types of problems they've had with mood previously," said Dr. Lee Cohen of Massachusetts General Hospital, one of the study's co-authors.
Indeed, on The Early Show Wednesday, Dr. Catherine Spong, a pregnancy specialist with the National Institute for Child Health and Human Development,
The study does not deal with postpartum depression — the depression that sets in after delivery and that is often blamed on hormonal changes. The research looks only at depression during pregnancy, a condition far less understood.
But, says Spong, "This study provides critical information for pregnant women with major depression.
"Even though it was previously thought that pregnancy protected against recurring episodes of depression, relapses continue to occur. This is vitally important for these women."
No one knows how many pregnant women are on antidepressants, but it's safe to say millions of women of childbearing age take them. Medco Health Solutions estimates 8.4 million American women ages 20 to 44 take antidepressants.
Other research has shown risks to the fetus — including possible heart defects — from antidepressant use during pregnancy.
"Drugs rarely, if ever, are actually studied in pregnancy to determine whether they are safe," Spong observes. "It's important to look at what type of antidepressant is being used and when it's being used during pregnancy. Although antidepressants generally are considered to be safe during pregnancy, some have been linked to complications, such as complications of the developing baby's heart as well as the withdrawal syndrome that occurs after birth. These are, in general, very rare, though."