Oral contraceptive exposure in newly pregnant women not linked to birth defects

New BMJ study provides important knowledge for pharmacists and their patients

A new study published in the British Medical Journal found that oral contraceptive exposure at onset or during pregnancy did not appear to be associated with an increased risk of major birth defects.

Researchers said the study could offer reassurance to women who become pregnant after missed or late oral contraceptive doses as well as women who intentionally become pregnant soon after discontinuing oral contraceptives.

 “I think the findings are comforting, and it does build on existing literature,” Lisa Kroon, PharmD, Professor at the University of California, San Francisco’s (UCSF) School of Pharmacy, told Pharmacy Today. “If a woman mistakenly continued using oral contraceptives during the early part of pregnancy, it didn’t increase the risk of birth defects.”

Using Danish health registries, four exposure groups were studied and prevalence of major birth defects—about 25 per 1000 births—was consistent across each group. Nearly 70% of the mothers stopped using oral contraceptives more than 3 months before pregnancy; 21% never used oral contraceptives; 8% used oral contraceptives until 0–3 months before pregnancy; and 1% used oral contraceptives during early pregnancy.

“This provides more concrete time periods,” said Kroon.

Kroon said as pharmacists’ scope of practice expands, this kind of knowledge is increasingly important in making sure women are getting the proper care they need.

Under SB 493 in California, pharmacists will be able to initiate the prescribing of self-administered hormonal contraceptives after asking patients to complete a questionnaire, as well as administering a blood pressure test and discussing dosing with them.

Kroon, who has been active in the law’s implementation, said questions about current hormonal contraceptive use and pregnancy status are part of the screening assessment patients undergo with pharmacists.

“While we’re not replacing the care of an OB/GYN, this is absolutely an important area for pharmacists to know about if you’re speaking to women about oral contraceptives,” said Kroon. 

 

Updated February 2, 2016