Intra-amniotic maternal hemorrhage in preterm labor: a case report.

A primigravid women was transferred to hospital because of preterm labor at 32 weeks' gestation with no vaginal bleeding. Hematologic studies showed severe anemia. Ultrasound examination revealed polyhydramnios and a clot around the umbilical cord without retroplacental hematoma. Diagnostic amniocentesis revealed heavily blood stained fluid, but HbF was not detected. With a clinical diagnosis of intra-amniotic maternal hemorrhage, immediate cesarean section was performed. The mechanism of intra-amniotic maternal hemorrhage is discussed.