in nuevo progresso, a five-minute walk from the u.s.der, pharmacist miguel mejia says he only sells abortion pills to people who have a prescription. the majority buying them are young americans. >> reporter: medication abortions account for more than half of all abortions in the united states. according to guttmacher, an organization that supports abortion rights. >> medication abortion is accomplished using two sets of pills. the first is mifepristone. what that does is causes weakening of the attachment of the pregnancy to the uterine wall. the second causes the uterus to contract and expel the pregnancy. those medications work together to be synergistic to end the pregnancy. >> reporter: emma's friend only had high smystoprostol pills. she experienced cramping and bled heavily. >> i thought it had been successful. i was very happy to, in my mind, no longer be pregnant. about a week and a half passed and all the symptoms started coming back slowly. >> reporter: another at-home test showed she was still pregnant. >> misoprostol alone