Second-trimester spontaneous abortion, the IUD, and infection.

Nineteen cases of spontaneous second-trimester abortion associated with the intrauterine device (IUD) are reviewed and compared to 30 cases of spontaneous second-trimester abortion not associated with the IUD. Fifteen of the IUD's were Dalkon shields and four were Lippes loops. 16 of the 19 IUD-associated abortions began either with prolonged rupture of membranes or signs and symptoms of infection. Infection occurred in 18 or 19 of the cases (95%) but only 30% of the comparison group. Eleven major complications occurred in eight patients in the IUD group but only 8 complications occurred among 7 patients in the comparison group. It is suggested that when the IUD remains in utero during pregnancy, it may be a causal factor in second-trimester spontaneous abortion, and that intrauterine infection is the distinguishing characteristic of such cases. Mechanisms are suggested by which the IUD might cause infected abortion.