Does midtrimester delta OD450 of amniotic fluid reflect severity of Rh disease?
Thirty-two patients with Rh-immunized pregnancies had amniocenteses between 16 and 20 weeks’ gestation. Serial amniotic fluid values of delta optical density at 450 nm were studied to predict the severity of Rh disease. A value greater than 0.15 indicated severe Rh immunization. Values less than 0.09 indicated mild or no Rh disease; delta optical density at 450 nm between 0.09 and 0.15 require further evaluation to determine the trend. Midtrimester amniocentesis is a simple technique that helps to determine which patients may or may not require fetal blood sampling.
