Barbara Duden discussed "quickening"—the first stirrings of a fetus that are detectable by the mother
formerly, the onset of quickening was sort of the defining confirmation that a person was pregnant
Duden 94: "A woman might be under suspicion of pregnancy, or have been pregnant in hindsight, but without her own witness, no woman was definitely pregnant."
this carried over into the legal realm
James Mohr: "The common law did not formally recognize the existence of a fetus in criminal cases until it had quickened ... The upshot was that American women in 1800 were legally free to attempt to terminate a condition that might turn out to be a pregnancy until the existence of that pregnancy was incontrovertibly confirmed by the perception of fetal movement"
Duden: "Physicians attacked quickening as a criterion because they wanted to challenge the court's reliance on women and jury matrons" (82); they want ultimately to "bypass society's dependence on the testimony of women" (96)