Increased paracetamol use during pregnancy is associated with language learning delays, a new study has found.
Earlier studies have found associations between the use of paracetamol, known in the US acetaminophen, during pregnancy and poorer child communication skills.
But those studies used measures of language development that were less precise than the methods applied in the current study, said study lead Megan Woodbury, a graduate student at the University of Illinois.
The research was conducted as part of the Illinois Kids Development Study, which explores how environmental exposures in pregnancy and childhood influence child development.
Woodbury said: “The previous studies had only asked pregnant people at most once a trimester about their acetaminophen use.
“But with IKIDS, we talked to our participants every four to six weeks during pregnancy and then within 24 hours of the kid’s birth, so we had six time points during pregnancy.”
The language analyses involved 298 2-year-old children who had been followed prenatally, 254 of whom returned for further study at age three.
For the two-year-olds, the researchers turned to the MacArthur-Bates Communicative Development Inventories, which asks a parent to report on the child’s vocabulary, language complexity and the average length of the child’s longest three utterances.
Comparative biosciences professor emerita, Susan Schantz, said: “We wanted to collect data at that age because it’s the period called ‘word explosion,’ when kids are just adding words every day to their vocabulary.”
Parents were asked to select words their child had used from a list of 680 words.
The parents assessed their child again at three years, comparing their language skills to those of their peers.
The analysis linked paracetamol use in the second and third trimesters of pregnancy to modest but significant delays in early language development.
Woodbury said: “We found that increased use of acetaminophen – especially during the third trimester – was associated with smaller vocabulary scores and shorter ‘mean length of utterance’ at two years.
Schantz added: “At age three, greater acetaminophen use during the third trimester was related to parents ranking their kids as lower than their peers on their language abilities.
That outcome was seen primarily in male children.”
The most dramatic finding was that each use of acetaminophen in the third trimester of pregnancy was associated with an almost two-word reduction in vocabulary in the two-year-olds.
Woodbury saidL “This suggests that if a pregnant person took acetaminophen 13 times – or once per week – during the third trimester of that pregnancy, their child might express 26 fewer words at age tewo than other children that age.”.
Foetal brain development occurs throughout pregnancy, but the second and third trimesters are especially critical times, Schantz said.
“Hearing is developing in the second trimester, but language development is already starting in the third trimester before the baby is even born,” she added.
“It’s thought that acetaminophen exerts its analgesic effect through the endocannabinoid system, which is also very important for foetal development,” Woodbury said.
The findings now need to be tested in larger studies, the researchers said.
Until then, mothers should not be afraid to take paracetamol for fever or serious pain and discomfort during pregnancy.
Conditions like a very high fever can be dangerous and using a drug like paracetamol will likely help.
Schantz said: “There aren’t other options for people to take when they really need them.
“But perhaps people should use more caution when turning to the drug to treat minor aches and pains.”
