KANSAS CITY, Mo. — The birth control pill Opill could soon be available for women without a prescription.

Executives at Perrigo, the drug maker, say this could be an important new option for the estimated 15 million women in the U.S. who currently use no birth control or less effective methods to prevent pregnancy.

The FDA has said it has serious reservations about broad access to the drug before making it widely accessible. Meanwhile, health regulators say research shows some women and young teenagers have trouble understanding how to use it properly.

According to Dr. Kristen Wootton at Saint Luke’s Health System, Opill is a progesterone only pill which have a shorter half-life compared to estrogen and progesterone pills. Wootton says this means the pill must be taken diligently at the same time every day to be effective, which could be problematic if women have with consistency.

Wootton says it’s also important for women to know if taking progesterone only pills are safe for them, because they could have adverse health effects in some women.

Health regulators with the FDA are concerned about the reliability of the drug if it’s sold without a prescription. In Opill’s main study, nearly 30 percent of women took more pills than they were supposed to. Unlike others pills that contain both estrogen and progesterone, consistency is even more crucial with this birth control pill and its ability to block pregnancy.

According to Perrigo’s global vice president of women’s health, Fredrique Welgryn, “We have no doubt that our data clearly shows that women of all ages can safely use Opill in the over-the-counter setting.”

It is not currently marketed in the U.S., but is being sold without a prescription to women in the U.K. If approved, insurers would have to cover over-the-counter birth control and would require a regulatory change by the Department of Health and Human Services.

The FDA is expected to make a final decision this summer.