Past Pill Use Doesn't Lower Fertility
Study: Pregnancy Rate Same for Past Users, Nonusers of Oral Contraceptives
May 8, 2007 (San Diego) -- Women who stop the birth control pill and then try to get pregnant succeed just as quickly as women who have not taken oral contraceptives before trying to conceive, a new study suggests.
The impact that using the birth control pill has on future fertility has been debated for years. Some studies have shown women have difficulty getting pregnant once they stop oral contraceptives, while other research has found they have an easier time.
"Studies have been mixed," says Maureen Cronin, MD, PhD, a researcher for the new study, presented at the 55th Annual Clinical Meeting of the American College of Obstetricians and Gynecologists. "The majority of studies suggest there is a slight delay in return to fertility after using birth control pills," she says, "and that within 6 to 12 months fertility is normalized."
But her study found no such lag and no substantial differences in pregnancy rates between pill users and nonusers. "We did the study to lay the question to rest," says Cronin, the head of global medical affairs for women's health care for Bayer Schering Pharma in Berlin. The pharmaceutical giant, which makes two types of birth control pills, Yasmin and Yaz, funded the study.
In the past, some experts have also suggested that after taking hormones such as the pill a woman shouldn't or couldn't get pregnant right away after stopping. A delay in trying to conceive, some say, allows the body to get back to normal. Cronin says her study also proves that notion incorrect. "Your body does not need to 'recover' from the pill," she says.
Cronin's team followed 2,064 women for two years; all were participating in the European Active Surveillance Study on Oral Contraceptives and had stopped taking birth control pills to become pregnant.
One cycle after stopping the pill, 21.2% of the women were pregnant, Cronin found. This is comparable to the naturally occurring pregnancy rate per cycle, which experts say is between 20% and 25%.
A year after stopping the oral contraceptives, 79.4% of the women were pregnant; again the rate corresponds with those reported in women planning a pregnancy who had not used the pill.