A study of nearly 500,000 women by researchers at the University of Pittsburgh Medical Center, in the September 18, 2007, Annals of Internal Medicine, found that nearly 50% of women taking a prescription drug that could cause birth defects did not receive warnings to avoid pregnancy. The authors note that the pregnancy risks of a drug should be discussed with women before they begin taking it.
Experts say the seriousness of a life-threatening lung disorder found six times more often in infants born to mothers who take antidepressants during pregnancy is not being adequately conveyed to women while they are considering whether to use the drugs.
The disorder, persistent pulmonary hypertension (PPHN), occurs when a newborn does not adjust to breathing outside the womb. PPHN refers to high pressure in the lungs' blood vessels which prevents the body's oxygen-poor blood from entering the lungs to absorb oxygen, and leaves the infant with not enough oxygen into the bloodstream.
On July 19, 2006, the FDA ordered a PPHN warning for the labels of the selective serotonin reuptake inhibitor antidepressants (SSRI's), based on a February 9, 2006 study in the New England Journal of Medicine, and issued a Public Health Advisory that stated:
"A recently published case-control study has shown that infants born to mothers who took selective serotonin reuptake inhibitors (SSRI's) after the 20th week of pregnancy were 6 times more likely to have persistent pulmonary hypertension (PPHN) than infants born to mothers who did not take antidepressants during pregnancy."
Two week later on August 1, 2006, the American College of Obstetricians and Gynecologist issued a press release warning that the use of SSRI's and selective norepinephrine reuptake inhibitors (SNRI's) during pregnancy should be individualized based on their respective risks and benefits, and specifically warned that Paxil should be avoided due to the potential risk of fetal heart defects, PPHN and other negative effects.
SSRI's sold in the US include Paxil marketed by GlaxoSmithKline, Prozac by Eli Lilly, Zoloft by Pfizer, and Celexa and Lexapro sold by Forest Laboratories, along with various generic versions of the drugs. The closely-related class of SNRI antidepressants also carry birth defects warnings and include Wyeth's Effexor and Lilly's Cymbalta.
In any given year in the US, at least eighty-thousand pregnant women are prescribed SSRI's, according to a study in the May 2005, Journal of American Medical Association. The CDC recently reported that antidepressants were the most prescribed class of drugs in the country in 2005. The fact that the overall prescribing rate is higher than for any other drugs indicates that a large number of pregnant women may be taking antidepressants without knowledge of the risks to the unborn fetus.
Overall, respiratory failure affects nearly 80,000 newborns per year, and it is responsible for as many as half of all infant deaths. Nearly one-third of all newborns with respiratory failure are born at term or near-term, and are at risk for PPHN, according to the April 2007 article, "Pulmonary Hypertension, Persistent-Newborn," by Dr Robin Steinhorn, head of the Division of Neonatology at Children's Memorial Hospital in Chicago and Professor at Northwestern University Medical School, in eMedicine from WebMD.
Dr Steinhorn also notes that an increased incidence of PPHN is reported for mothers who use SSRI's during the last half of their pregnancies.
As recently as 15 years ago, the reports says, the mortality rate for PPHN infants reached 40%, and the prevalence of major neurologic disability was 15-60%. However, the introduction of extracorporeal membrane oxygenation (ECMO) and other new therapies has had a major effect on reducing the mortality rate, yet the prevalence of major neurologic disabilities among surviving newborns remains approximately 15-20%.
Dr Steinhorn reports that Glass and colleagues compared the neurodevelopmental outcome of 103 neonates following ECMO and 37 without ECMO at age 5 and states:
"Major disability, which was defined as mental disability, motor disability, sensorineural impairment, or seizure disorder, was present in 17 of children in whom ECMO had been used. The mean full-scale, verbal, and performance intelligence quotient (IQ) scores of children who received ECMO treatment were within the normal range; however, as a group, the scores were significantly lower than in children who had not had ECMO (96 vs 115)."
According to the report, infants who survive following ECMO have a higher rate of rehospitalization for nonpulmonary and surgical conditions, and the rate of sensorineural disabilities in infants who survive averages 6% and developmental delay occurs in 9%.
Because the prevalence of hearing loss is high, the report recommends that an automated hearing test should be administered before discharging the baby and hearing should be reassessed when he or she is 6-months-old and again, as the results indicate.
Dr Steinhorn also notes that an increased frequency of social problems, academic difficulties at school age and higher rates of attention deficit disorder are reported in children who received ECMO.
