Acetaminophen use during pregnancy is safe, and evidence to support a link between acetaminophen and the development of childhood asthma is weak, a meta-analysis published in the Archives of Disease in Childhood suggests.

“The meta-analysis has a higher level of evidence and supports the use of acetaminophen during pregnancy,”  Joyce M. Knestrick, PhD, CRNP, FAANP, associate professor and director of distance education at Georgetown University School of Nursing and Health Studies told The Clinical Advisor.

To determine the association between acetaminophen exposure during pregnancy or infancy and the subsequent development of childhood asthma, Mweene Cheelo, MSc, from the Allergy and Lung Health Unit, Centre for Epidemiology and Biostatistics at the Melbourne School of Population and Global Health, University of Melbourne, Australia, and colleagues conducted a meta-analysis of 11 studies conducted between 1967 and 2013.

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Of the studies, five found increased odds that acetaminophen exposure during the first trimester of pregnancy was linked to development of childhood asthma. The studies, however, demonstrated a high degree of disparate results, noted the investigators.

Dissimilar results were also found in the two studies that examined the effects of acetaminophen exposure during the second trimester: one study reported an odds ratio (OR) of 1.06, while the other reported an OR of 2.15. Two more studies tested use of acetaminophen during the third trimester and found a weak association (pooled OR = 1.63, 1.22, and 0.74).

Additionally, the last three studies reviewed the impact of acetaminophen use during the entire pregnancy, but these results were also heterogeneous.

“The studies we see in this article have a small number of subjects and limited data,” cautioned Knestrick. “More clinical trials and cohort studies are needed to determine the safety of drugs during pregnancy, particularly in acetaminophen use during pregnancy.”

Acetaminophen, however, may be considered as a treatment option for primary-care providers treating pregnant patients with fever, according to Knestrick.

“Use other non-medicinal measures first,” suggested Knestrick. In situations where acetaminophen use is unavoidable, primary-care providers should reiterate the instructions on the bottle to patients.

“I always tell patients more isn’t always better,” advised Knestrick. “The point is to be judicious. We don’t know all the side effects of many medications during pregnancy.”

The results of this study can be helpful for everyday practice, as the meta-analysis contains an overview of available data available on acetaminophen use during pregnancy.

“Most patients come in with some knowledge, and if they don’t, significant others or other family members may,” said Knestrick. “[Providers] can look at this meta-analysis and it will be very helpful to make patient-centered decisions.”


  1. Cheelo M et al. Arch Dis Child. 2014; doi:10.1136/archdischild-2012-303043.