Over the past few years, millions of women have gone to the pharmacy to fill their birth control prescription, or visited the doctor to have an intrauterine device inserted, and learned their birth control is fully covered, without a copayment. Some of these women used to pay hundreds of dollars a year out-of-pocket for birth control. But among the Affordable Care Act’s dramatic advancements for women’s preventive health is a provision that requires insurance companies to cover birth control without a copay.

However, while 48.5 million women are eligible for this benefit, recent reports make it abundantly clear that some health insurance carriers continue to charge women for their prescriptions or make them jump through unnecessary hoops to receive the birth control method they and their doctor agree is best for them.

Recognizing this troublesome trend, the National Women’s Law Center reviewed insurance companies’ plan documents in 15 states to see how they are covering women’s health care, including birth control. They found that some insurance companies are not providing the coverage the law requires, forcing women to pay more or go without the contraceptive best suited to their health and needs.

This is a clear defiance of the law’s mandate.

Some insurers restrict access to certain birth control methods, such as the ring, patch and IUD, by forcing women to undergo “step therapy” — or what’s known colloquially as the try-and-fail method. This means a woman may be forced to use one birth control method, such as the pill, regardless of whether it works for her, before getting coverage for the ring, patch, IUD or other method she and her doctor have decided is best for her. Some insurers also create an unnecessary barrier by requiring prior authorization, an extra step that gives the insurer the right to reject a doctor’s prescription.

These violations occur even though the ACA requires insurance companies to cover the pill, ring, IUD and all other Food and Drug Administration-approved methods of birth control — not a curated selection.

Figuring out which birth control method is right for an individual is a personal decision that should be made with a woman’s health care provider alone. That’s why Planned Parenthood Federation of America and the American Congress of Obstetricians and Gynecologists fought so hard for the preventive benefit in the first place, and it’s why we’re calling on the Obama administration to ensure this provision is enforced.

As medical providers, we see firsthand

there is no one-size-fits-all method of birth control. Some women have medical conditions that preclude their ability to use particular methods. Others may suffer from side effects when they use certain contraceptives; while conversely, some may seek out hormonal methods to regulate conditions such as endometriosis. Some women have lifestyles that just don’t allow for birth control that depends on daily doses for effectiveness. The bottom line is that each woman must be able to access the method that best fits her particular health needs without barriers — including cost.

Many forms of birth control are prohibitively expensive for many women if they must foot the bill out of pocket. IUDs are one of the most effective forms of birth control and they can be used for up to 12 years. In fact, the American Academy of Pediatrics recommends long-acting reversible contraceptives such as the IUD as first-line methods for teenagers. But an IUD typically costs between $500 and $1,000 — a price tag few could afford until the women’s preventive benefit took away the cost barrier.

One-third of all American women earn less than $47,000 per year for a family of four. No wonder more than half of all American female voters ages 18 to 34 have struggled with the cost of birth control at some point, and as a result have used birth control inconsistently.

Thanks to the birth control benefit, women and families saved more than $483 million in out-of-pocket costs for the birth control pill — an average of $269 per woman — in the first year alone. More importantly, they prevented unintended pregnancies.

We must continue on this path. Offering women the full range of FDA-approved birth control methods is an essential part of health care, and we are grateful that this provision was included in the ACA. Now, the Obama administration should take immediate steps to ensure that the law is enforced so all women get the health care they need and deserve.

Deborah Nucatola, M.D., is senior director of medical services at Planned Parenthood Federation of America; Hal C. Lawrence III, M.D., FACOG is executive vice president and CEO of the American Congress of Obstetricians and Gynecologists.