Nearly two-thirds of women with private healthcare have plans that cover free birth control, according to a study released by the Guttmacher Institute on Thursday.

The number of women whose birth control is covered by their insurance has spiked under ObamaCare, according to polling compiled by the reproductive rights nonprofit. Before the law, just one-quarter of women said their health plans covered birth control.

{mosads}Contraception coverage is now a required part of most private health plans under a controversial piece of the Affordable Care Act. The “birth control mandate” had been a sticking point among conservatives, and more than 60 lawsuits were filed challenging the Obama administration on it.

Before the law went into effect, only about 15 percent of women said their insurance covered oral contraception, the most popular method nationwide.

“Large numbers of women are now able to obtain highly effective birth control methods without co-pays or deductibles, making it easier for them to choose the method they can use most consistently and effectively to avoid an unplanned pregnancy,” said Adam Sonfield, a senior policy analyst who led the study.

Still, the study found instances in which insurance plans were denying coverage or restricting access to some types of contraception, particularly among plans offered by religious groups.

Researchers also criticized the Supreme Court’s decision this summer that ruled some employers, such as Hobby Lobby, are exempt from covering contraception.

Birth control costs can vary dramatically. Oral contraceptives can cost between $15 and $80 each month, according to a national analysis by the Center for American Progress.