Placental Abnormalities

In the UK, hemorrhage was the major factor in more than 150 maternal deaths between 1985 and 19961, and remains one of the main causes of admission of pregnant women to intensive care units2–4. In countries with limited resources, the toll from obstetric hemorrhage is greater5,6 and a significant number of the deaths from hemorrhage are associated with substandard care and/or inadequate obstetric facilities1,7. Placental abnormalities are a major contributor to obstetric hemorrhage. Placental abruption and placenta previa are associated with odds ratios for postpartum hemorrhage (PPH) of 13 (99% CI 7.6–12.1) and 12 (99% CI 7.2–23), respectively, representing the highest of any major risk factors identified by the Royal College of Obstetricians and Gynaecologists (RCOG)8. Placental abnormalities including morbidly adherent placentas (accreta, increta, percreta) are rare conditions, but increasing in incidence and associated with high risk of catastrophic hemorrhage. In one series, placental abnormalities accounted for 36% of pregnancy-related deaths due to hemorrhage9.