The finding reinforces the notion that antidepressants should not be used by pregnant women in the absence of a clear need that cannot be met through alternative approaches, said researchers from Brigham and Women's Hospital, Vanderbilt University, MetroWest Medical Center and Tufts Medical Center.
"Preterm birth is a major clinical problem throughout the world and rates have been increasing over the past two decades," said lead author Krista Huybrechts, from the Division of Pharmacoepidemiology and Pharmacoeconomics at Brigham and Women's Hospital and Harvard Medical School.
"At the same time, rates of antidepressant use during pregnancy have increased approximately four-fold. Therefore it is essential to determine what effects these medications have on pregnancy," Huybrechts said.
Huybrechts and colleagues conducted a systematic review and meta-analysis of published studies that evaluated women who took antidepressants during pregnancy and had information on gestational age at birth.
"We studied 41 papers on this topic and found that the available scientific evidence is becoming clearer that antidepressant use in pregnancy is associated with preterm birth," said senior author Adam Urato, a Maternal-Fetal Medicine specialist at Tufts Medical Center and MetroWest Medical Center.
"The complication of preterm birth did not appear to be due to the maternal depression but rather it appears likely to be a medication effect," Urato said.
Of the 41 studies which the authors reviewed, the majority showed increased rates of preterm birth in patients taking antidepressants.
The association was strongest with use in the third trimester. There was no evidence of a beneficial effect or reduction in preterm birth with antidepressant use.
"Preterm birth is the leading cause of infant death and it is also a major contributor to both short and long-term illness," said Urato.
"Pregnant women with depression need proper treatment and our results should not be seen as an argument to ignore depression in these patients," said Huybrechts.
"These drugs may be necessary in some pregnant women with severe depression in whom other approaches are inadequate. However, for many others, non-drug treatments, such as psychotherapy, will help, and aren't associated with complications like preterm birth," said Huybrechts.
The study appears in the journal PLOS ONE.