The baby blues don’t always wait until after baby is born.

Pregnancy hormones were long thought to protect a mother from feeling the effects of chronic depression during pregnancy.

But recent findings published in the Journal of the American Medical Association refute that conventional wisdom.

Clinicians at Massachusetts General Hospital say some women can and do suffer major depression during pregnancy.

The study revealed many women would like to spend their entire pregnancy free of medications for fear the drugs might harm the developing fetus. Previous research has shown antidepressant use during pregnancy might cause fetal heart defects. And use during the last three months of pregnancy has been associated with jitteriness and irritability in newborns.

In the current study, researchers tracked the pregnancies of about two-hundred women who chose whether to continue with prescribed antidepressants or to modify their dose if they did stay on medication.

Regardless, forty-three percent had a major depression relapse during pregnancy. And more than two-thirds of the women who discontinued their medication experienced major depression.

Eighty-two women kept taking antidepressants throughout pregnancy. They were less likely to develop recurrent depression than those who discontinued medication. But even about a twenty-five percent of them still relapsed. In light of the study’s findings, researchers advise doctors and patients to carefully weigh the risk of dangerous depression and compare it with the risk of exposing the fetus to the pharmaceuticals … to help both mother and baby keep free of the blues.