Pregnancy-associated mortality after birth, spontaneous abortion, or induced abortion in Finland, 1987-2000.
This article, from the February 2004 (Volume 190, Issue 2) edition of the American Journal of Obstetrics and Gynecology, concludes that the mortality rate associated with abortion is 2.95 times higher than that associated with pregnancies carried to term. The study included the entire population of women 15 to 49 years of age in Finland between 1987 and 2000.
This was a record-based study. That means that the results were derived not from interviews with individual subjects, but in this case by linking birth and abortion records to death certificates.
The annnual death rate of women who had abortion in the previous year was also 46% higher than that of non-pregnant women.