A large cohort study in the USA has found that there is no statistically significant association between the use of paracetamol during pregnancy and either preterm births or birth weights, although it did identify a link to lower odds of a baby being born large for its gestational age
There is no statistically significant evidence that paracetamol has a negative effect on how early a baby is born or on its birth weight, according to novel research led by environmental scientists at the University of North Carolina (UNC) Gillings School of Global Public Health. Paracetamol is known in the USA as acetaminophen and commonly sold under the brand name ‘Tylenol’.
The study examined a large cohort of pregnancies in the USA, drawn from a US National Institutes of Health (NIH) programme data. It found that paracetamol use during pregnancy did not significantly affect gestational age or average birth weight.
When birth weight was assessed in the context of gestational age – classified as small-for-gestational-age (SGA) or large-for-gestational-age (LGA) – the researchers did identify an association between paracetamol use and lower chances of a baby being born large for its gestational age.
“Given the widespread use of acetaminophen, these findings offer important reassurance about its safety with respect to birth timing and infant size,” said Dr. Rebecca Fry, the ‘Carol Remmer Angle Distinguished Professor’ and chair of environmental sciences and engineering at UNC, and senior author of the study.
Paracetamol is widely used during pregnancy to treat pain and fever and it is one of the few over-the-counter analgesics considered a first-choice option in this period. Recent studies have produced mixed findings as to whether the drug affects foetal development or birth size and timing and this research aimed to add further evidence to that debate by directly examining the relationship between paracetamol use and birth outcomes.
The research team, led by Fry and first author Dr. Katelyn Huff, a postdoctoral researcher at the Gillings School, studied 8,957 mother–infant pairs drawn from 36 sites participating in the NIH’s Environmental influences on Child Health Outcomes study. The analysis examined the relationship between paracetamol use during pregnancy and four birth outcomes:
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- preterm birth
- birth weight
- SGA
- LGA.
Around 59 per cent of the mothers in the study reported using paracetamol at some point during pregnancy. After adjusting for confounding factors, the researchers found that prenatal paracetamol use was associated with lower odds of LGA while identifying no association with preterm birth, birth weight or SGA.
The results offer reassurance for pregnant women who use paracetamol as directed, although the authors have noted that further research would be beneficial on dosing, timing and other possible health effects. While typical paracetamol use during pregnancy did not appear to raise birth risks in this study, women are still advised to discuss paracetamol use – along with any other medication – with their doctor during pregnancy.
For further reading please visit: 10.1093/aje/kwag110
