WASHINGTON – Free birth control led to dramatically lower rates of abortions and teen births, a large study concluded Thursday, offering strong evidence for how a bitterly contested Obama administration policy could benefit women’s health.

The project tracked more than 9,000 women in St. Louis, many of them poor or uninsured. They were given their choice of a range of contraceptive methods at no cost – from birth control pills to goof-proof options such as the IUD or a matchstick-sized implant.

When price wasn’t an issue, women flocked to the most effective contraceptives – the implanted options, which typically cost hundreds of dollars up-front. These women experienced far fewer unintended pregnancies, reported Dr. Jeffrey Peipert of Washington University in St. Louis in a study published Thursday.