Between 7% and 13% of women take an antidepressant during pregnancy. Doctors prescribe antidepressants because depression during pregnancy can lead to poor prenatal health and has been linked to premature birth, low birthweight babies and poor fetal growth.

The risks to a pregnancy from antidepressant use have been studied, but the results are inconsistent. Three major concerns have been identified. They are an increased risk for preterm birth, heart defects (cardiac malformations), and breathing problems for newborns, called neonatal respiratory distress.

A new study from researchers at University of California San Diego has added to the knowledge of antidepressant risks by studying how the dose of an antidepressant and the time of use during pregnancy affect risks for preterm birth, cardiac malformation or neonatal respiratory distress.

The findings of the study are published in Pediatrics. The researchers looked at 226,932 pregnancies, including 15,000 in which antidepressants were used.

Among the women who took antidepressants, use was divided into five patterns:

  • low dose with reduction during the first trimester
  • low dose continued through pregnancy
  • moderate dose with reduction during first trimester
  • moderate dose continued through pregnancy
  • high dose throughout pregnancy.

The different patterns of use were compared with each other and with women who did not take antidepressants (the control group to see how each pattern affected the risk of adverse neonatal outcomes.)

Results: Low dose antidepressant use with reduction of use during the first trimester was not linked to any increased risks. However, low dose use continued through pregnancy was linked to a 36% increased risk of neonatal respiratory distress…compared to a 5.4% risk for neonatal respiratory distress among all the women in the study (those who took antidepressants and those who did not).

  • Moderate dose continued through pregnancy was linked to a 31% increased risk of preterm birth. The risk of preterm birth among all the women in the study was 7.6%.
  • All the patterns of use were linked to an increased risk of neonatal respiratory distress that increased as the dose increased. High dose use throughout pregnancy was linked to a more than double the risk…as well as a 78% increase in risk for preterm birth.
  • The risk of cardiac malformations among all the women in the study was 1.2%, and the researchers found no evidence that any pattern of antidepressant use increased that risk.

The researchers conclude that antidepressants should continue to be used in pregnant women whose pregnancies would be at risk from depression. They should be treated with the lowest dose of antidepressant that is still effective. Women who need a moderate to high dose antidepressant during pregnancy should be cautioned about the increased risk for preterm birth and neonatal respiratory distress.                                   

Source: Study titled “Prenatal Antidepressant Use and Risk of Adverse Neonatal Outcomes,” by researchers at University of California San Diego, published in Pediatrics.