Obese women who use oral contraceptives to prevent pregnancy can now heave a sigh of relief as researchers have identified ways to make birth control pills more effective.
Making birth control pills work as well in obese women as in women of a normal body mass index has long been a challenge as obesity affects how a woman's body clears contraceptive hormones.
Either a slight increase in the pill dose, from a very low dose to a low dose pill; or using the pill continuously without a "period week" off, appeared to counteract the changes that obesity causes, the findings showed.
"Birth control pills have been shown in a large population study to fail at a higher rate in women who are obese," said Ganesh Cherala, an assistant professor at Oregon State University in the US.
It takes longer for the pill to reach a steady level in obese women, with possible impacts on efficacy of birth control, and putting them at greater risk for a pill failure if they forget to take a pill or take it later.
"The strategies that we studied can be, and are currently being used by women, but now we know that they help to counteract the adverse effects of weight on contraceptive hormones," said Alison Edelman, an associate professor of obstetrics and gynaecology at Oregon Health & Science University.
The study appeared in the journal Contraception.
