Time magazine reports that a study of more than 9,000 women, conducted over a three year period at the Washington University School of Medicine and published October 4 in the journal Obstetrics & Gynecology, found that when they were provided with free birth control, their incidence of unintended pregnancy and abortions fell far below the national average.

One reason is that most of the women chose reversible long-term birth control methods such as implants or IUDs. Other women paying out of pocket for contraception may be more inclined to prefer alternatives such as birth control pills, whose costs are paid over time rather than in a bigger up-front charge, but are more sensitive to human error.