Gov. Jack Dalrymple signed legislation Tuesday that would make North Dakota the nation's most restrictive state on abortions, banning the procedure if a fetal heartbeat can be detected -- something that can happen as early as six weeks into a pregnancy, AP reports. The Republican governor also signed into law another measure that would make North Dakota the first to ban abortions based on genetic defects such as Down syndrome, and a measure that requires a doctor who performs abortions to be a physician with hospital-admitting privileges. The measures, which would take effect Aug. 1, are fueled in part by an attempt to close the state's sole abortion clinic in Fargo. Dalrymple said in a statement that the fetal heartbeat bill was a direct challenge to Roe v. Wade. "Although the likelihood of this measure surviving a court challenge remains in question, this bill is nevertheless a legitimate attempt by a state legislature to discover the boundaries of Roe v. Wade," Dalrymple said. Pro-abortion advocates have promised a legal fight that they say will be long, costly and unwinnable for the state. Dalrymple said in his statement that the legislature "should appropriate dollars for a litigation fund" before the session ends in early May.