Causative factors in first trimester abortion failure

To evaluate the main contributors to failed first trimester abortions. Forty-two cases of unintentional continued pregnancy were detected among 23,000 termination procedures performed between 1989 and 1995. The patients were diagnosed either at follow-up visits or at the time of operation due to abnormal pelvic findings or discrepancy between the expected and obtained tissue. The failure rate was found to be 0.18%. Among the patients with failed abortion 8 patients had unsuspected anomalies; two of these patients conceived with an intrauterine device in position; 7 patients had uterine malposition (2 markedly anteverted and 5 markedly retroverted), and 2 patients had leiomyomas. No genital disorder was identified in the remaining 25 women. Among these 25 women, 10 had gestations beyond 8 weeks, for which suction curettage followed by sharp curettage was performed. Among the remaining 15 in whom only suction curettage was used for termination, 13 had less than 6 weeks of gestation at the time of pregnancy termination. When a termination fails, when scanty tissue is obtained, or when doubt exists about the termination, an extrauterine pregnancy must be ruled out and other causes of termination failure should be considered such as technical failure, uterine anomaly, or malposition.