After a study found that taking paracetamol during pregnancy may negatively affect male offspring, expectant mothers are being advised to limit their intake of the common pain relief drug. Paracetamol is routinely used around the world to treat aches and pains and reduce fevers — "paracetamol" is another name for acetaminophen, the active ingredient in Tylenol — and it’s usually one of the safest drugs to use during pregnancy, according to Fit Pregnancy. However, new research from the University of Copenhagen suggests that there may be a new side effect to worry about if it’s used over a prolonged period of time — specifically that paracetamol can inhibit the development of “male behavior” in mice.
According to the research published in the journal Reproduction on Thursday, researchers found that male mice babies exhibited less masculine behaviors when they were exposed to paracetamol in the womb. The Danish-led study suggests that the painkiller can interfere with a male’s testosterone production, affecting their sex drive and making them less likely to mate with females than other rodents in the study.
The researchers also found that the male mice given doses of paracetamol in utero were less likely to mark their territory with urine and exhibit “aggressiveness” toward an “intruding male.”
“It is very worrying,” David Møbjerg Kristensen, lead author of the study, told iNews of the findings. “We have demonstrated that a reduced level of testosterone means that male characteristics do not develop as they should.”
However, some academics aren’t entirely convinced that the study accurately reflected how humans take paracetamol, such as how often and how much of the drug the pregnant mice were given it. According to The Australian, experts said “the size, regularity and speed of administration of the doses were all too high.”
As BuzzFeed’s Tom Chivers, a science writer for the site, reported, the mice were given a dose of 150 milligrams of paracetamol per kilogram of body weight per day — which equates to about three times the recommended dose a human should take.
“In the animal study, exposure to paracetamol was daily from 7 days post-coitum to birth,” Ieuan Hughes, professor of paediatrics at the University of Cambridge, told News Corp Australia, explaining that it’s not comparable to the way the drug is used by expectant mothers.
He continued, “Pregnant women generally take analgesics like paracetamol intermittently for symptoms and generally for a very short period.”
While this study does provide interesting insight into drug’s capabilities, many experts are saying that pregnant women should not be alarmed by the study’s findings and should continue to take paracetamol in moderation when necessary. However, before taking any medication when you’re pregnant, it’s always best to check in with your doctor first to make sure all risks are discussed ahead of time.