Unsafe abortions kill many Tanzanian women, according to a recent study, but the deaths result from several factors and women in some regions die much more often than others.

Birth control is hard to get, and public health clinics lack trained staff and vacuum aspiration kits used to perform abortions. In addition, the legality of abortion is ambiguous, forcing many women to try to do it themselves or see illegal abortion providers. Of one million unintended pregnancies in 2013, the study found, 39 percent ended in abortion.

The study, done by the Guttmacher Institute, Tanzania’s national medical research institute and the country’s leading medical school, and published in PLOS One, was based on surveys of hospitals and clinics and interviews with Tanzanian doctors.

Although Tanzania ratified the African Union’s 2005 Maputo Protocol on women’s rights — which endorsed abortion rights — and also recognizes colonial-era British case law permitting abortion in some circumstances, national law mandates 14-year sentences for anyone “unlawfully” performing an abortion and seven years for women who try to make themselves miscarry — but without defining “unlawfully,” said Sarah C. Keogh, a Guttmacher Institute researcher and the study’s lead author.