A new study by scientists at Harvard Medical School, Vanderbilt University, and Tufts University School of Medicine has confirmed the findings of numerous previous studies that have linked maternal use of antidepressants during pregnancy with an increased risk of preterm birth.
According to the Centers for Disease Control, preterm birth affects nearly 500,000 babies – 1 of every 8 infants born in the United States. It was the leading cause of infant death in 2009 and is also the leading cause of neurological disabilities in children.
“Each year, preterm birth affects nearly 500,000 babies – that’s 1 of every 8 infants born in the United States.” — U.S. Centers for Disease Control and Prevention
The researchers performed a comprehensive review of the medical literature for studies that addressed preterm birth and antidepressant usage, and selected 41 studies published between 1993 and 2012, that compared preterm birth rates among women who took antidepressants (principally SSRI and SNRI antidepressants) during pregnancy with a control group of pregnant women who did not take the drugs. They chose in particular studies that adjusted their findings based upon the possible influence of other factors that have been associated with preterm birth, such as maternal age, smoking, and alcohol use. Such “confounders” can distort findings unless they are addressed statistically.
Eleven studies also addressed the question of confounding by depression itself by comparing women who took antidepressants during pregnancy to another group of women with a diagnosis of depression or other psychiatric disorder but did not take antidepressants during pregnancy. Data from similar studies were pooled together in a process known as a meta-analysis that permits scientists to better estimate the strength of an association.
The meta-analysis determined that even after adjusting their findings for various confounders, including depression and other psychiatric disorders, maternal use of antidepressants during pregnancy increased the risk of preterm birth by 61%. Antidepressant usage late in pregnancy (typically third trimester) doubled the risk of preterm birth.
The authors stressed that while some believe there is a link between depression and preterm birth, “expert review panels have concluded that there is no clear association between depression and preterm birth.”