The epidemiology of placenta previa in the United States, 1979 through 1987.

OBJECTIVE: Placenta previa can cause serious, occasionally fatal complications for fetuses and mothers; however, data on its national incidence and sociodemographic risk factors have not been available.

STUDY DESIGN: We analyzed data from the National Hospital Discharge Survey for the years 1979 through 1987 and from the Retrospective Maternal Mortality Study (1979 through 1986).

RESULTS: We found that placenta previa complicated 4.8 per 1000 deliveries annually and was fatal in 0.03% of cases. Incidence rates remained stable among white women but increased among black and other minority women (p < 0.1). In addition, the risk of placenta previa was higher for black and other minority women than for white women (rate ratio 1.3, 95% confidence interval 1.0 to 1.7), and it was higher for women > or = 35 years old than for women <20 years old (rate ratio 4.7, 95% confidence interval 3.3 to 7.0). Women with placenta previa were at an increased risk of abruptio placentae (rate ratio 13.8), cesarean delivery (rate ratio 3.9), fetal malpresentation (rate ratio 2.8), and postpartum hemorrhage (rate ratio 1.7).

CONCLUSION: Our findings support the need for improved prenatal and intrapartum care to reduce the serious complications and deaths associated with placenta previa.