• Press Release

Acetaminophen Use During Pregnancy Associated With Elevated Rate of Language Delay in Girls, Mount Sinai Researchers Find

  • New York, NY
  • (January 10, 2018)

In the first study of its kind, researchers from the Icahn School of Medicine at Mount Sinai found an elevated rate of language delay in girls at 30 months old born to mothers who used acetaminophen during pregnancy, but not in boys.

This is the first study to examine language development in relation to acetaminophen levels in urine.

The study will be published online January 10 at 3:28 am EST in European Psychiatry.

Acetaminophen, also known as paracetamol, is the active ingredient in Tylenol and hundreds of over-the-counter and prescription medicines. It is commonly prescribed during pregnancy to relieve pain and fever.  An estimated 65 percent of pregnant women in the United States use the drug, according to the U.S. Centers for Disease Control and Prevention. 

The Swedish Environmental Longitudinal, Mother and Child, Asthma and Allergy study (SELMA) provided data for the research. Information was gathered from 754 women who were enrolled into the study in weeks 8-13 of their pregnancy. Researchers asked participants to report the number of acetaminophen tablets they had taken between conception and enrollment, and tested the acetaminophen concentration in their urine at enrollment. The frequency of language delay, defined as the use of fewer than 50 words, was measured by both a nurse’s assessment and a follow-up questionnaire completed by participants about their child’s language milestones at 30 months.

Acetaminophen was used by 59 percent of the women in early pregnancy. Acetaminophen use was quantified in two ways: High use vs. no use and women who did not report any use as the comparison group. For the urine analysis, the top quartile of exposure was compared to the lowest quartile.

Language delay was seen in 10 percent of all the children in the study, with greater delays in boys than girls overall. However, girls born to mothers with higher exposure—those who took acetaminophen more than six times in early pregnancy—were nearly six times more likely to have language delay than girls born to mothers who did not take acetaminophen.  These results are consistent with studies reporting decreased IQ and increased communication problems in children born to mothers who used more acetaminophen during pregnancy.  

“Given the prevalence of prenatal acetaminophen use and the importance of language development, our findings, if replicated, suggest that pregnant women should limit their use of this analgesic during pregnancy,” said the study’s senior author, Shanna Swan, PhD, Professor of Environmental and Public Health at the Icahn School of Medicine at Mount Sinai. “It’s important for us to look at language development because it has shown to be predictive of other neurodevelopmental problems in children.”

"These new data suggest that the use of acetaminophen poses a risk for pregnant women" said Carl-Gustaf Bornehag, Professor, Karlstad University, Sweden, and adjunct Professor at Icahn School of Medicine at Mount Sinai, the study’s lead author.

Both the number of tablets and concentration in urine were associated with a significant increase in language delay in girls, and a slight but not significant decrease in boys.  Overall, the results suggest that acetaminophen use in pregnancy results in a loss of the well-recognized female advantage in language development in early childhood.

The SELMA study will follow the children and re-examine language development at seven years.

Other researchers from Mount Sinai include Avraham Reichenberg, PhD, Professor of Psychiatry.  Other institutions involved in this study include Karlstad University in Sweden, Institute of the Ruhr-University in Germany, and Lund University in Sweden.

This study was supported by grants from the National Institute of Environmental Health Sciences, the Swedish Research Council Formas and from the County Council of Varmland. 


About the Mount Sinai Health System

The Mount Sinai Health System is New York City's largest academic medical system, encompassing eight hospitals, a leading medical school, and a vast network of ambulatory practices throughout the greater New York region. Mount Sinai advances medicine and health through unrivaled education and translational research and discovery to deliver care that is the safest, highest-quality, most accessible and equitable, and the best value of any health system in the nation. The Health System includes approximately 7,300 primary and specialty care physicians; 13 joint-venture ambulatory surgery centers; more than 415 ambulatory practices throughout the five boroughs of New York City, Westchester, Long Island, and Florida; and more than 30 affiliated community health centers. The Mount Sinai Hospital is ranked on U.S. News & World Report's "Honor Roll" of the top 20 U.S. hospitals and is top in the nation by specialty: No. 1 in Geriatrics and top 20 in Cardiology/Heart Surgery, Diabetes/Endocrinology, Gastroenterology/GI Surgery, Neurology/Neurosurgery, Orthopedics, Pulmonology/Lung Surgery, Rehabilitation, and Urology. New York Eye and Ear Infirmary of Mount Sinai is ranked No. 12 in Ophthalmology. Mount Sinai Kravis Children's Hospital is ranked in U.S. News & World Report’s “Best Children’s Hospitals” among the country’s best in four out of 10 pediatric specialties. The Icahn School of Medicine is one of three medical schools that have earned distinction by multiple indicators: ranked in the top 20 by U.S. News & World Report's "Best Medical Schools," aligned with a U.S. News & World Report "Honor Roll" Hospital, and No. 14 in the nation for National Institutes of Health funding. Newsweek’s “The World’s Best Smart Hospitals” ranks The Mount Sinai Hospital as No. 1 in New York and in the top five globally, and Mount Sinai Morningside in the top 20 globally.

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