Risk of Acetaminophen and Fever During Pregnancy

A study published February 24 in JAMA Pediatrics raises concern about women's use of acetaminophen during pregnancy, while a separate study published the same day in Pediatrics raises concern about the effect of maternal fever during pregnancy.

In the JAMA Pediatrics study, researchers at the Fielding School of Public Health at the University of California, Los Angeles, found that women who take acetaminophen during pregnancy had a higher risk of having a child with attention-deficit/hyperactivity disorder (ADHD)-like behaviors or a hyperkinetic disorder (HKD), raising doubts about the pain reliever's safety for use by pregnant women.¹

The study enrolled 64,322 live-born children and mothers enrolled in the Danish National Birth Cohort during 1996–2002. Acetaminophen use during pregnancy was assessed prospectively via 3 telephone interviews during pregnancy and 6 months after childbirth.

The researchers conclude that maternal acetaminophen use during pregnancy is associated with a higher risk for HKDs and ADHD-like behaviors in children. Children whose mothers used the painkiller while pregnant had a 13% to 37% higher risk of having an HKD, being prescribed methylphenidate, or having ADHD-like behaviors at age 7 years. Stronger associations were observed with use in more than one trimester during pregnancy: children of mothers who used acetaminophen for more than 20 weeks into pregnancy had a 50% higher risk for HKD or ADHD-like behaviors.

Because of the ubiquity of acetaminophen exposure and the frequency of ADHD or HKD diagnoses, "these results are of public health relevance," the authors note, but further investigation about the safety of acetaminophen during pregnancy are needed.

Still, pregnant women might not want to toss the Tylenol just yet. …

Meanwhile, the Pediatrics study found that fever during pregnancy might have negative effects on the health of the child.²

Researchers in Denmark performed a meta-analysis of the literature since 1990 addressing health outcomes of prenatal fever exposure in humans. Their study included 46 studies that referred to maternal fever in general populations during the first trimester or before conception.

They found that the risk of neural tube defects, congenital heart defects, and oral clefts was greater among children whose mother had fever during pregnancy.

They also found "some evidence that antipyretic medications may have a protective effect" when used to treat fever during pregnancy.

The study authors concluded that there is "substantial evidence to support an adverse impact of maternal fever during pregnancy," and that these harmful effects included short- and long-term health problems. They call for further research to assess the effect of children’s exposure to maternal fever in utero.

—Michael Gerchufsky

References

1. Liew Z, Ritz B, Rebordosa C, Lee P-C, Olsen J. Acetaminophen use during pregnancy, behavioral problems, and hyperkinetic disorders [published online ahead of print February 24, 2014]. JAMA Pediatr. doi:10.1001/jamapediatrics.2013.4914.

2. Dreier JW, Andersen A-MN, Berg-Beckhoff G. Systematic review and meta-analyses: fever in pregnancy and health impacts in the offspring [published online ahead of print February 24, 2014]. Pediatrics. doi:10.1542/peds.2013-3205.