Saturday, December 4

The reason why some women can get pregnant on the pill



Birth control pill contraceptive pill calendar routine nobody close-up the contraceptive pill is supposed to be 99% effective in preventing pregnancies when taken perfectly (ie, at the same time every day).

But despite that, it’s not unheard of for women to get pregnant while on the pill.

When taken imperfectly so, at different times of the day, or with the odd missed pill that effectiveness rate drops to 91%. Because of this, it was previously assumed that any unwanted pregnancies on the contraceptive pill would be due to the woman not taking it properly.

Cropped shot of an unrecognizable teenage girl drinking medication

But new scientific research suggests there might be another cause of unplanned pregnancies occurring despite the pill or other forms of hormonal contraception – and it’s one that’s beyond your control.

A study carried out by researchers at the University of Colorado Anschutz Medical Campus has identified a particular gene that can break down the hormones commonly found in contraceptive pills and other hormonal contraceptive options, therefore reducing their effectiveness.

The research, which was published this week in the Obstetrics & Gynecology journal, assessed 350 healthy women with a median age of 22.5 years old, all of whom had had the contraceptive implant in place for anywhere between one and three years.

Results revealed that 5% of women in the study had a gene called CYP3A7*1C, which tends to exist in foetuses but is usually ‘switched off’ prior to birth.

In a small proportion of women, however, this gene stays with them into adulthood, creating an enzyme in the body called CYP3A7 which is known to break down hormones.

That enzyme… may put women at a higher risk of pregnancy while using contraceptives, especially lower dose methods, Aaron Lazorwitz, MD, lead author of the study, said.

Disappointed hispanic girl getting unexpected result from pregnancy test kit. Sad young latina woman sitting alone on her bed.

Lazorwitz suggested the discovery may trigger a change in how doctors treat women with unplanned pregnancies while on contraception.

When a woman says she got pregnant while on birth control, the assumption was always that it was somehow her fault. But these findings show that we should listen to our patients and consider if there is something in their genes that caused this, Lazorwitz said.

The gene in question is detectable via genetic screening, which the scientist said means that women who are found to have it may in future be able to receive specifically tailored treatment to prevent any further unwanted pregnancies. And that’s a pretty important development for us.