Note that after Penicillin became available to control infections, the number of deaths stabilized during the 1950s at about 250 deaths per year.

By 1966, with abortion still illegal in all states, the number of deaths had dropped steadily to about 120 per year.

The reason was new and better antibiotics, better surgical procedures, and the establishment of intensive care units in hospitals.  

By 1972, the year before Roe v. Wade, the U.S. Supreme Court decision (1973) allowing legal abortion on demand in all 50 states, maternal deaths from illegal abortion had fallen to 39; there were also 25 additional deaths that year resulting from legal abortions (in 16 states that had limited abortions, such as California and New York).

Thus, according to U.S. statistics, legalization of abortion did not save thousands of lives, as is often claimed.

The numbers of maternal deaths dropped most dramatically from the introduction of antibiotics.

To repeat, in 1967, the first state legalized abortion. California in 1967 and New York in 1970 legalized abortion on demand.

By 1966, the number of maternal deaths from illegal abortion was about 120 and by 1972, the year before abortion was legalized nationwide, 39 women died as a result of illegal abortion.

More than likely, there were not many illegal abortions, and antibiotics were the single most important factor in cutting maternal death from illegal abortion.

Making abortion legal was not necessary.