During the first trimester, when it was believed that the procedure was safer than childbirth, the Court ruled that a state government could place no restrictions on women's ability to choose to abort pregnancies other than imposing minimal medical safeguards, such as requiring abortions to be performed by licensed physicians.[7] From the second trimester on, the Court ruled that evidence of increasing risks to the mother's health gave states a compelling interest that allowed them to enact medical regulations on abortion procedures so long as they were reasonable and "narrowly tailored" to protecting mothers' health.[7] From the beginning of the third trimester on—the point at which a fetus became viable under the medical technology available in the early 1970s—the Court ruled that a state's interest in protecting prenatal life became so compelling that it could legally prohibit all abortions except where necessary to protect the mother's life or health