Experts Say Birth Defect Risks Outweigh Benefits of SSRIs
Drug makers looking to increase profits with the sale of selective serotonin reuptake inhibitor antidepressants to pregnant women claim that untreated depression poses a grave risk to the unborn fetus, but a new study reports that the use of antidepressants, and not the depression itself, increases the risk of lower fetal age and preterm birth.
The study in the August 2007 American Journal of Psychiatry examined the effects of depression and antidepressant use on fetal age and risk of preterm birth in 90 women who were divided into three groups: (1) forty-nine women treated with antidepressants for more than 50% of their pregnancy; (2) twenty-two briefly treated or not treated with the drugs during pregnancy; and (3) a comparison group of 19 healthy pregnant women.
The researchers found that the average fetal age at birth was 38.5, 39.4 and 39.7 weeks in the three groups, respectively, and that the rates of preterm birth were 14.3 percent, 0 percent and 5.3 percent, respectively.
The study showed that the rate of admission to the special-care nursery more than doubled at 21% for newborns exposed to antidepressants, compared to 9% of infants born to mothers who were not treated with the drugs and 0% in the control group. "This result was surprising to us, as we had anticipated that depression and anxiety during pregnancy would be associated with an increased risk of preterm birth," wrote Dr Rita Suri and colleagues from the University of California, Los Angeles.
"The two groups of women with depression -- those who were treated with antidepressants and those who were not -- had similar degrees of depression and anxiety during pregnancy," the authors of the study note.
The new study is alarming because, in May 2005, researchers at the University of Pittsburgh reported that, in any given year, at least 80,000 pregnant women in the US are prescribed SSRIs which include Paxil marketed by GlaxoSmithKline; Zoloft from Pfizer; Prozac and Cymbalta marketed by Eli Lilly, and Celexa and Lexapro from Forest Labs.
The drugs are still being prescribed to pregnant women despite the fact that more than 4 years ago, in June 2004, the FDA revised the SSRI labels to warn that infants exposed to the drugs in the womb can develop problems requiring prolonged hospitalization, respiratory support and tube feeding.
When issuing the warning, the agency said it had received hundreds of preliminary reports of adverse effects in newborns over the last decade and that the most common were trouble eating, irritability, body rigidity and respiratory problems. More SSRI-related birth defects have surfaced in every year since that FDA warning in 2004.
In September 2005, Glaxo sent a "Dear Doctor" letter about a Paxil label change based on data from the National Birth Defects Prevention Study, which found that women who took SSRIs were more likely to have an infant with omphalocele, an abnormality in which the infant's intestine or other abdominal organs protrude from the navel, with the strongest effect reported with Paxil, accounting for 36% of all SSRI exposures.
In addition, the "Dear Doctor" letter advised of an association between mothers taking SSRI's and giving birth to an infant with craniosynostosis, a congenital defect present at birth in which the connections between sutures-skull bones prematurely close during the first year of life, which causes an abnormally-shaped skull.
In December 2005, Glaxo notified doctors of a new warning added to the Paxil label about the risk of major congenital malformations in infants born to women taking Paxil during the first trimester of pregnancy and the FDA also issued an advisory warning about the risk of congenital malformations, especially of the heart, and changed Paxil's category from C to D. Category D means a drug has been found to harm the human fetus.
In July 2006, the FDA issued another public advisory, this time warning that infants exposed to SSRI's were six times more likely to develop the life-threatening lung disorder persistent pulmonary hypertension (PPHN) than infants who were not exposed.
The warning was based on a study in the February 9, 2006, New England Journal. After the study was released, lead author Dr Christina Chambers told the Wall Street Journal that she heard from women all over the country who had babies born with PPHN after taking SSRI's during pregnancy.
According to Dr Robin Steinhorn, Head, Division of Neonatology; Children's Memorial Hospital of Chicago, Department of Pediatrics, Professor, Northwestern University Medical School in eMedicine from WebMD, accessed on August 15, 2007:
"Recent data suggest that the PPHN syndrome may occur as often as 2-6 cases per 1000 live births. PPHN is a frequent complicating factor in the term or near-term newborn with parenchymal lung disease, such as MAS (meconium aspiration syndrome) or pneumonia. An increased incidence of PPHN is reported for mothers who use selective serotonin reuptake inhibitors (SSRI's) during the last half of their pregnancies."
