Do miscarriages occur more frequently after abortions?

A Boston study by a group who have aggressively done abortions denied any increase after one abortion, but, after two or more abortions, they did find a "two-to three-fold increase in risk of first trimester spontaneous abortions [miscarriages]," as well as "losses up to 28 weeks gestation." Levin et al., "Association of Induced Abortion with Subsequent Pregnancy Loss," JAMA, vol. 243, no. 24, June 27, 1980, pp. 2495-2499

Of a group of 52 women who had induced abortions 10-15 years previously and who were followed very closely during that length of time, it was found that one-half (27) had no problem with subsequent pregnancies. There was one ectopic pregnancy, eight subsequent — but long-delayed — conceptions, and three women with permanently blocked tubes. Of the remaining 11 women, there were 33 pregnancies with 14 early and 3 midtrimester losses, 6 premature deliveries, and only 10 full-term births. Hilgers et al., "Fertility Problems Following an Aborted First Pregnancy." In New Perspectives on Human Abortion, edited by S. Lembrych. University Publications of America, 1981, pp. 128-134

A high incidence of cervical incompetence resultant from abortion has raised the incidence of spontaneous abortions to 30-40%. A. Kodasek, "Artificial Termination of Pregnancy in Czechoslovakia," Internat’l Jour. of GYN & OB, vol. 9, no. 3, 1971

Women who had one abortion had a 17.5% miscarriage rate in subsequent pregnancies, as compared to a 7.5% rate in a non-aborted group. Richardson & Dickson, "Effects of Legal Termination on Subsequent Pregnancy," British Med. Jour., vol. 1, 1976, pp. 1303-4

Women who had delivered their first pregnancy had (in the second pregnancy) the "best reproductive performance." Those who had a spontaneous miscarriage on the first had "the highest frequency of an early loss." Those with induced abortion on their first had "the highest frequency of late spontaneous abortion and premature delivery." Koller & Eikham, "Late Sequelae of Induced Abortion in Primagravida" Acta OB-GYN Scand, 56 (1977) p. 311.