A retrospective analysis of pathological placental implantation — site and penetration

Abstract

Objectives: To determine the incidence of pathologically implanted placenta, i.e placenta previa and accreta, at the Maternity Hospital of Kuwait. In addition the study aimed to identify the risk factors for such conditions, and test the hypothesis that previous cesarean section increases the likelihood of abnormal placentation. Methods: Analysis of all deliveries in the Maternity Hospital of Kuwait with identification of cases of placenta previa, placenta accreta, previous cesarean section and manual removal of placenta. Information was obtained from the medical records of the hospital between 1981 and 1992 except for the period 1990–1991 due to incomplete information as a consequence of the Iraqi invasion. The incidences of these conditions were calculated followed by identification of risk factors for placenta accreta and previa. Results: The incidence of placenta previa was 0.5% and that of placenta accreta 9.5 per 100 000 deliveries. Placenta previa and previous cesarean section were found to be significant predisposing factors for placenta accreta. The increased risk for placenta accreta in the presence of these factors was much less than that reported in the international literature. Abnormal placentation was responsible for 34% of peripartum hysterectomies. Conclusion: Placenta accreta and previa are major causes of massive obstetric hemorrhage. They are interrelated with a common predisposing factor, cesarean section. Even though the rate of cesarean section and placenta previa is increasing, the incidence of placenta accreta remains stable in Kuwait.