Evaluation of intra-amniotic administration of 120 gm of urea with 5 mg of prostaglandin F2α for midtrimester termination of pregnancy between 20 and 24 weeks' gestation

The occasional finding of signs of life in fetuses delivered following intra-amniotic administration of 80 gm of urea and 5 mg of prostaglandin F2α suggested that the dose of 80 gm of urea was inadequate beyond the nineteenth week. Protocol modifications were made, and the metabolic effects of intra-amniotic administration of 120 gm of urea used beyond the nineteenth week were compared to those of the 80 gm dose of urea used in patients prior to the twentieth week. The 120 gm urea dose was well tolerated. The peak blood urea nitrogen (at 4 hours after instillation) was higher with 120 gm of urea (36.4 mg/dl) than with 80 gm of urea (24.6 mg/dl) (p < 0.05). Small decreases in the platelet count (14% of control) and serum fibrinogen (11%), sodium (2%), potassium (7%), and carbon dioxide (11%) levels and a 5% increase in peak serum osmolality were found. Following the change in protocol, fetal heart activity has been absent at 3 hours after instillation in all cases