JAMA July 29, 1939 has maternal mortality statistics from 1933-1937:

Year	Septic  Abortion Deaths	non-septic Abortion Deaths	Total Maternal Deaths
1933	2037	640	12885
1934	2204	570	12859
1935	2167	602	12544
1936	1801	680	12182
1937	1531	582	10769

Following WW2 there was an improvement in antibiotics and techniques and the Baby Boom led also to improvements in Obs/Gyn medical techniques and protocols.

"Legalized abortion: Effect on national trends of maternal and abortion-related mortality (1940 through 1976)."
(Am J Obstet Gynecol, September 15, 1978, vol. 132, no. 2, p. 211-214.)

The Suction Aspiration technique, inroduced in Europe in the early to mid 1960s began to be used in US hospitals in the late 60s once more improving the safety of the procedure.

We can then check the first legalized phase for comparison

 Based on Christopher Tietze, M.D." Induced Abortion: A World View", 1983 . New York: The Population Council, 1983).
 
 

Year	Legal Abortions performed	Deaths  Legal Abortions	Deaths  Illegal Abortions
1970 1971		36 54	109   65
1972		24	41
1973	615,831	25	21
1974	763,476	26	7
1975	854,853	29	4
1976	988,267	11	3
1977	1,079,430	17	4
1978	1,157,776	9	7
1979	1,251,921	18	0
1980	1,297,606	9	2

NOTE
One thing we can do with this chart is estimate the number of illegal abortions performed.

In 1973 eg there were 615,831 legal abortions and these resulted in 25 deaths and the deaths from illegal abortions numbered 21.  Since in truth the abortion providers both legal and illegal were at that time pretty similar in skill we could anticipate that there were also ~600,000+ illegal abortions performed or in total ~1,200,000 abortions in 1973.  There really was not an increase in the number of abortions performed by legalizing - just a huge decrease in women's deaths from them, as the skill, and surroundings in which abortions were performed, improved.

Some abortion opponents claim the declining mortality numbers are the result of improved antibiotics but this alone just won't cut it I'm afraid. Not particularly in examining the numbers from the 1970's.

    Year               Mortality/Abortions      Mortality/Births
   1970                  19.0                16.0
   1971                  11.0                14.9
   1972                   4.1                15.2
   1973                   3.4                12.5
   1974                   2.9                12.4
   1975                   2.8                10.3
   1976                   0.9                10.2
   1977                   1.3                 9.8
   1978                   0.6                 9.7
   1979                   1.2                 8.0
   1980                   0.6                 7.5
   1981                   0.4                 7.2
   1982                   0.8                 7.9
   1983                   0.7                 8.0

What these charts very accurately shows is that the one result of legalizing abortion is that the mortality rate from the procedure plummeted.

If  you're really interested in learning the reason for this decline in mortality get a copy of :

Journal of the American Medical Association 1992 Dec 9;268(22):3231-9

Induced termination of pregnancy before and after Roe v Wade. Trends in the mortality and morbidity of women. Council on Scientific Affairs, American Medical Association.
 

"The mortality and morbidity of women who terminated their pregnancy before the 1973 Supreme Court decision in Roe v Wade are compared with post-Roe v Wade mortality and morbidity...Deaths from illegally induced abortion declined between 1940 and 1972 in part because of the introduction of antibiotics to manage sepsis and the widespread use of effective contraceptives. Deaths from legal abortion declined fivefold between 1973 and 1985 (from 3.3 deaths to 0.4 death per 100,000 procedures), reflecting increased physician education and skills, improvements in medical technology, and, notably, the earlier termination of pregnancy."

What has become clear is that if you are really interest in something other than handing over the 'abortion business' to what we would ordinarily call 'organized crime' which will inevitably result in a return to frequent deaths, as it did in Romania and Poland when they reversed their policy, then what we must do is keep it in the hands of legally trained medical professionals.