Women taking over-the-counter ibuprofen during early pregnancy could potentially be damaging their unborn baby girl's future fertility irreversibly, according to a new study.

The research published in Human Reproduction suggests that taking the common painkiller for only two days within the first 24 weeks of pregnancy could deplete the unborn daughter's ovarian germ cells, causing a reduced fertile period and possibly infertility later in life. These cells would later differentiate into cells that make the follicles where the eggs are developed and released. 

Dr Séverine Mazaud-Guittot of the University of Rennes, the lead author of the study, said: 'Baby girls are born with a finite number of follicles in their ovaries and this defines their future reproductive capacity as adults. […] A poorly stocked initial reserve will result in a shortened reproductive life span, early menopause or infertility - all events that occur decades later in life.'

Two to seven days' exposure to ibuprofen dramatically reduced the germ cell stockpile in human foetal ovaries. After this exposure, the ovaries did not recover fully from the damage, the scientists found.

'This suggests that prolonged exposure to ibuprofen during fetal life may lead to long-term effects on women's fertility and raises concern about ibuprofen consumption by women during the first 24 weeks of pregnancy,' Dr Mazaud-Guittot said. 

The study used tissue samples from 185 aborted 7 to 12-week-old human fetuses, and cultured the tissue in the laboratory. Half of the group were exposed to ibuprofen and half of the group were not, as a control. The researchers found that tissue exposed to realistic concentrations of ibuprofen, comparable to those if a mother had taken the painkiller, had approximately half the number of ovarian germ cells. 

'We found there were fewer cells growing and dividing, more cells dying and a dramatic loss of germ cell numbers, regardless of the gestational age of the fetus,' said Dr Mazaud-Guittot. 'We saw cell death as early as after two days of treatment.'

It is currently estimated that 30 percent of pregnant women take ibuprofen within the critical 24-week fetal development period. Fortunately, the advice on ibuprofen consumption during pregnancy does not need to change much in light of this study. The NHS currently advises expectant mothers to not take the drug before 30 weeks gestation. Earlier studies have associated the painkiller with an increased risk of fetal malformation and miscarriage.

Prof Ying Cheong, reproductive medicine researcher at the University of Southampton, who was not involved in the study, praised the study. 'The work is of excellent quality and represents important scientific advancement. We now need longitudinal epidemiological data to further confirm these observations as to whether exposure in early pregnancy relates to reduced fertility,' he said. 'Generally speaking, ibuprofen should be used in pregnancy sparingly but the current evidence should not be used to "scare-monger" women into not using these rather effective simple analgesics at all.'

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Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.