Acetaminophen, long the mainstay of a pregnant woman’s pain-relief arsenal, has been linked to behavioral problems in children born to mothers who used it during pregnancy.

Research published Monday by the journal JAMA Pediatrics found that a woman’s use of acetaminophen at 18 and 32 weeks of pregnancy was associated with greater odds that when the resulting child was 7 years old, his or her mother would report a range of problematic behaviors.

Compared to women who reported no acetaminophen use at 18 weeks of pregnancy, those who took the medication at that point of gestation were 42 percent more likely to report hyperactivity and 31 percent more likely to report conduct problems in the children they bore.

Women who took acetaminophen at 32 weeks of pregnancy were 29 percent more likely than women who did not to report emotional difficulties in their child at age 7. Children born to mothers who took acetaminophen late in their pregnancy were 46 percent more likely to experience a wide range of behavioral difficulties than were children born to moms who took no acetaminophen at that point.

Finding a link between acetaminophen use during pregnancy and an outcome affecting the child is no proof that acetaminophen is the cause of the outcome. But the authors contend that the study results do heighten concerns that fetal exposure to acetaminophen can give rise to neurodevelopmental problems.