"It is important to note the unstable ground of these shifting political alliances. Twenty-first-century anti-abortion and anti-birth-control activists condemn Sanger for her post-World War I alliance with American eugenicists. But Sanger herself was anti-abortion, as were many of the eugenics organizations. The American Eugenics Society, in A Eugenics Catechism, declared abortion was murder, except to save the life of or prevent serious injury to the mother."
Thomas C. Leonard, Illiberal reformers: race, eugenics & American economics in the progressive era (Princeton: Princeton University Press, 2016), 216n39 (in the context of an exposure of the illiberalism of a eugenicism that, however, wasn't just characteristic of progressivism, but rather "crossed all ideological boundaries (115)). Leonard cites Diane Paul, "What Was Wrong with Eugenics? Conflicting Narratives and Disputed Interpretations," Science and education 23 (2014): 265 (259-271), and Daniel J. Kevles, In the name of eugenics: genetics and the uses of human heredity (New York: Knopf, 1985), 92. If this transcription of A eugenics catechism is accurate, then the wording was "Abortion except on strict medical grounds is murder and eugenists [sic] do not advocate it except to save the life or serious injury of the mother." Sanger herself: "nothing short of contraceptives can put an end to the horrors of abortion and infanticide" (Woman and the new race (New York: Brentano's, 1920), 25, among, probably, other passages). Presumably, then, this means that the often tendentiously cited statement, "The most merciful thing that the large family does to one of its infant members is to kill it" (63), was a claim about the impersonally lethal "effects upon the child" (61) of the conditions created by the unavailability of contraception, not a claim that "the large family" should choose infanticide. (But I haven't really read any Sanger.)