Prostaglandin F2a(PGF2a) was injected intraamniotically in 122 patients between 14 and 20 weeks' gestation in the dosage schedule recommended by the drug manufacturer to induce abortion. Significantly more multiparous (47.5%) than primigrasida patients (21.5%) aborted within 16 hours, but the mean duration between PGF2ainjection and abortion was not significantly different. Complications occurred in 52 (42.6%) patients and included: fall in hematocrit of more than 5 percentage points, failure to abort within 48 hours after injection, infection requiring antibiotic therapy, cervical laceration or fistula, and uterine rupture. The atypical dilatation and effacement of the cervix occurring with PGF2a-induced contractions may possibly lead to cervical incompetence with later pregnancies. Although the efficacy of PGF2aas an abortifacient is confirmed, the large complication rate with the procedure cannot be ignored.