Taking paracetamol or ibuprofen during pregnancy could affect an unborn child’s fertility in later life, researchers have suggested.
The study, conducted by researchers at the University of Edinburgh, also found that paracetamol and ibuprofen may affect the fertility of future generations, by reducing the number of egg- or sperm-producing cells during development.
They said the study gives further evidence that that certain medicines, including paracetamol, should be used with caution during pregnancy.
Current guidelines advise that, if necessary, paracetamol (acetaminophen) should be used at the lowest possible dose for the shortest possible time and ibuprofen should be avoided completely during pregnancy.
Scientists at the University of Edinburgh looked at the effects of paracetamol and ibuprofen on samples of human foetal testes and ovaries. They found similar effects using several different experimental approaches, including lab tests on human tissue samples and animal studies.
In vitro human tissues exposed to either drug for one week had reduced numbers of germ cells, which give rise to sperm and eggs. Ovaries exposed to paracetamol for one week had more than 40% fewer germ cells. After ibuprofen exposure, the number of cells was almost halved. Testicular tissue had around a quarter fewer germ cells after exposure to paracetamol or ibuprofen.
The researchers also found that exposure to paracetamol or ibuprofen triggers mechanisms in the cell that make changes in the structure of DNA, called epigenetic marks. These marks can be inherited, meaning the effects of painkillers on fertility could be passed on to future generations.
The study was published in Environmental Health Perspectives
(online, 16 April 2018) and funded by the Medical Research Council, Wellcome and the British Society of Paediatric Endocrinology and Diabetes. Rod Mitchell, who led the research at the University of Edinburgh’s MRC Centre for Reproductive Health, said: “We would encourage women to think carefully before taking painkillers in pregnancy and to follow existing guidelines — taking the lowest possible dose for the shortest time possible.”
 Hurtado-Gonzalez P, Anderson R A, Macdonald J et al. Effects of Exposure to Acetaminophen and Ibuprofen on Fetal Germ Cell Development in Both Sexes in Rodent and Human Using Multiple Experimental Systems. Environmental Health Perspectives 2018. doi: 10.1289/EHP2307