When is the latest a woman can abort?

Depends on reason: Don't think there's a set gestational age limit for having an abortion. Abortion is legal if done before the fetus is viable (usually before 24 wk), or at anytime when abortion is necessary to protect the life or health of the woman, or if the fetus has a serious genetic defect or abnormality. If exact details are important, one should see a local ob-gyn, because there may be state law variations.