Raised nitric oxide levels may cause atonic postpartum hemorrhage in women with anemia during pregnancy

ObjectiveTo determine the association of hemoglobin (Hb) and plasma nitrite (PN) concentrations on admission to the delivery ward with the occurrence of atonic postpartum hemorrhage (PPH).MethodsOf 319 women admitted to the Department of Obstetrics and Gynecology, Dayrout General Hospital, Assiut, Egypt, for delivery in July 2010, 200, who were not considered to be at risk of atonic PPH, were eligible for inclusion. Plasma levels of Hb and nitrite were measured on admission. The third stage of labor was actively managed.ResultsA total of 22 participants had significantly raised PN levels (P < 0.001), 12 of whom developed PPH—with Hb levels of 9 g/dL or less and nitric oxide (NO) levels of 180 μM/L or greater. The other 10 women underwent over 6 hours of stressful labor prior to hospital admission.ConclusionEven moderate anemia can raise levels of NO and enhance its biologic effects, which in turn can result in uterine muscle relaxation and atonic PPH. Preventing or treating anemia during pregnancy could avoid these complications.