1650s, "the killing of infants," especially the killing of newborns or the unborn; 1670s, "one who kills an infant," from infant + -cide. Perhaps from French infanticide (16c.).
In Christian and Hebrew communities infanticide has always been regarded as not less criminal than any other kind of murder; but in most others, in both ancient and modern times, it has been practised and regarded as even excusable, and in some enjoined and legally performed, as in cases of congenital weakness or deformity among some of the communities of ancient Greece. [Century Dictionary]