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CDC Found Causal Link Between SSRIs and Birth Defects

— July 9, 2015



It was only a matter of time before the Centers for Disease Control (CDC) spoke out on the issue of taking SSRI antidepressants while pregnant and birth defects. The CDC found causal link between SSRIs and birth defects.

The study, led by Jennita Reefhuis, an epidemiologist in the birth defects branch of the CDC, looked at five of the most commonly used SSRIs, listed in ascending order:

  • Zoloft (sertraline)
  • Prozac (fluoxetine)
  • Paxil (paroxetine)
  • Celexa (citalopram)
  • Lexapro (escitalopram).

The team’s analysis was published in the BMJ this week. The study covered 17,952 mothers of children born with birth defects and 9,857 mothers of children without birth defects. All children were born between 1997 and 2009 at ten different medical centers. Of the 27,809 mothers, 1,285 took SSRIs during what is believed to be the “danger zone” of one month pre-conception through the first trimester. This danger zone is the period when babies in the womb are most susceptible.

While on out of every 33 babies born in the U.S. has some type of birth defect, researchers are still baffled as to the causes of most. The FDA issued an advisory warning about paroxetine and heart defects in December 2005. Since then, there have been numerous studies that have looked for causal links. All of these studies resulted in conflicting conclusions.

The CDC team wrote, “[T]he inconsistent reports have limited opportunities for clinicians to carefully evaluate the risk compared with benefit of specific SSRIs for given patient during pregnancy.”

The CDC study shows that certain SSRIs might be riskier than others. One thing the lawsuits have taught us clearly is that research in this area is all over the map, though.

Some studies, for example, have shown connections between sertraline and five different types of birth defects. The CDC, however, wasn’t able to confirm any such connection. Reefhuis commented that this finding was actually “reassuring” as sertraline was the most used drug among those studied.

The team found cause for concern when it came to paroxetine and fluoxetine, though. Babies whose mothers took paroxetine were more likely to have anencephaly, a condition where the infant is mission parts of the skull and brain and also has heart and abdominal wall defects. Those whose mothers took fluoxetine were more likely to have heart defects and a condition affecting one or more joints of the skull, called craniosyntosis.

While this may sound like a victory cry for certain plaintiffs, the connections between the drugs and the birth defects were quite small. As example, the risk of paroxetine leading to anencephaly rose from 2 in 10,000 births to 7 in 10,000 births. As Reefhuis said, “It is a doubling or more in some cases, but you have to keep in mind that that a doubling of small risk is still a small risk.”

The team acknowledged some limitations to their study, though. For instance, they didn’t have access to dosage information or reason for taking the drugs. However, Reefhuis mentioned a new CDC-funded study currently underway. This new study will examine the “missing” factors in Reefhuis’ study with a closer focus on babies born with the severest types of birth defects.


Link between some antidepressants and birth defects is confirmed

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