Obstetric implications of low-lying placentas diagnosed in the second trimester

Objectives: To determine the obstetrical outcome of pregnancies initially complicated by a low-lying placenta in the second trimester. Methods: We reviewed the obstetric outcome of all women with singleton deliveries from I January 1997 to 31 March 1999 and compared the 703 women with low-lying placentas (placentas in the lower uterine segment) with the 6938 women with placentas that were normally situated in the upper uterine segment at 16-22 weeks' gestation. Results: Pregnancies complicated by a low-lying placenta in the second trimester were not associated with anteparturn hemorrhage, preterm births, preterm prelabor rupture of membranes, pregnancy-induced hypertension, fetal growth restriction or cesarean births. However, they had a higher incidence of postpartum hemorrhage (odds ratio 1.768, 95% confidence interval 1.137, 2.748) than women with a normally situated placenta in the second trimester. Conclusions: Pregnant women with low-lying placentas in the second trimester have a higher incidence of postpartum hemorrhage and hence, it would be prudent to carefully manage the third stage of labor in these women. (C) 2003 International Federation of Gynecology and Obstetrics. Published by Elsevier Science Ireland Ltd. All rights reserved.