At the writing of the Constitution abortions were preformed routinely up to the "Quickening".
""Quickening is when a pregnant person starts to feel their baby's movement in their uterus (womb). It feels like flutters, bubbles or tiny pulses. Quickening happens around 16 to 20 weeks in pregnancy, but some people may feel it sooner or later.""
https://pubmed.ncbi.nlm.nih.gov/10297561/
""During the colonial period, the legality of abortion varied from colony to colony and reflected the attitude of the European country which controlled the specific colony. In the British colonies abortions were legal if they were performed prior to quickening. ""
So why would they think it need to be clarified any further?