For that reason, even the (pro-abortion) Guttmacher Institue admits that "In the United States, abortion-related maternal deaths declined sharply following the introduction of antibiotics in the 1940s." That'd be 30 years before the general legalization of abortion.
For some eye-opening information on this aspect, read The Myth of Mass Back-Alley Abortion Deaths.
ALL surgery-related deaths started dropping in the 30s and 40s due to antibiotics. EVERYONE knows this, but it’s more effective to talk about “back alley” abortion deaths regardless of the truth (there is a segment of the movie “Dirty Dancing” which promotes this myth).