In 1871, an unmarried twenty-five year old woman in Mexico City reportedly "fell prisoner to an emotional suffering that drowned her in a state of indescribable distress." According to the obstetricians of Mexico City's National Medical School, the señorita had become hysterical after having been impregnated and subsequently abandoned by her seductor. In order to restore her sanity, doctors insisted that the woman's seven-month fetus should be expelled prematurely by means of a surgical procedure called artificial premature birth. This paper uses medical writings to explore how Mexican doctors drew on ideas about hysteria and organic lesions in order to re-conceptualize the boundaries between "natural" and "unnatural" pregnancies, and in order to experiment with surgical methods of ending unwanted pregnancies. It also suggests that their efforts were in open defiance of an 1869 Papal declaration, which declared that the termination of pregnancy at any stage was a grave sin that merited excommunication. These debates—about fetal personhood and the interruption of pregnancy—cannot be separated from the context of Mexico's mid-century political climate, which was characterized by positivism in politics and scientific practice, on the one hand, and the secularizing impetus of Mexico's liberal reforma, on the other. The paper suggests that artificial premature birth was not just a novel abortive procedure—it was also part of the secularization of Mexican reproductive science. Secularization—however partial and contested—seemed to have occurred not just in state functions, but also in the epistemologies and ideologies surrounding reproduction and fertility control.