It’s long been known that the highly effective acne medication isotretinoin — marketed as Accutane and Roaccutane —  is tied to the risk of severe birth defects. But even with a special program in place to prevent conception in women taking the drug, each year two to three hundred women in the U.S. become pregnant while taking it, a new study shows.

The program, dubbed iPLEDGE, which was started in 2006 by the U.S. Food and Drug Administration, requires women who want a prescription for isotretinoin to use birth control or promise to abstain from intercourse and to take a pregnancy test before starting the drug and every month thereafter.

While the program may have reduced the number of pregnancies in women who take the drug, the number hasn’t been reduced to zero, according to the study published in JAMA Dermatology.

“This drug is really life changing for those with severe acne that is resistant to everything else,” said study coauthor Dr. Arash Mostaghimi, an assistant professor of dermatology at Harvard Medical School and Brigham and Women’s Hospital. “Even those who have had very mild acne can think about how it impacted them. Imagine how impactful it would be if it was severe and caused permanent scarring. I think of this as an opportunity to study the situation and to think about how we can improve the delivery of this medication to patients in the safest way possible.”

To take a closer look at the impact of iPLEDGE, Mostaghimi and his colleagues combed through data from the FDA’s Adverse Event Reporting System, which collects information on adverse events that have been reported by health-care providers, consumers and manufacturers.

The researchers found reports of 6,740 pregnancies among women taking isotretinoin between 1997 and 2017, which peaked at 768 pregnancies in 2006 and then began to decline, plateauing in 2011 at 218 to 310 per year. Among women of childbearing age who were registered for iPLEDGE in 2006 and 2009 to 2010, the pregnancy rates ranged from 33 per 10,000 to 65 per 10,000.

Just 41 per cent of the reports included the woman’s age. Among those reports, the average age of the women who became pregnant was 24.6 years. Overall, women aged 20 to 29 accounted for the highest number of reported pregnancies (1,510), therapeutic abortions (317) and miscarriages (227).

Minimize unplanned pregnancies

Mostaghimi hopes the discussion about isotretinoin won’t scare people with severe acne away from the drug. “I’ve seen such an improvement on people’s lives,” he said.

It’s unlikely that the number of pregnancies among women who are taking in isotretinoin will ever drop all the way to zero, said Dr. Hyagriv Simhan, vice chair for obstetrics at the UPMC Magee-Womens Hospital in Pittsburgh.

“No system is perfect,” said Simhan who was not involved in the new research. “But building in decision-support so doctors prescribing this medication could ask the right questions would go a long way to minimizing the number of unplanned pregnancies. Contraception is not perfect. But I think we could use it a lot better than we are.”

Since Accutane can damage the head, face, heart, central nervous system and limbs of a fetus, the prescribing information in Canada requires written consent from the patient, two negative pregnancy tests before treatment and the use of two reliable methods of birth control for women of child-bearing age.

In 2016, Canadian researchers also concluded that despite the strict guidelines, there were many failures in preventing pregnancy.