Production Rate and Sources of Amniotic Fluid at Term

Summary Flow measurements following drainage of the amniotic cavity in four normal patients at term indicated a production rate of amniotic fluid of 16–42 ml. per hour. Serial measurements of oestriol and urea in the amniotic fluid and comparison with concentrations in the urine of the newborn infants indicated that the fetal urine contributed 2–5 per cent of the amniotic fluid in 3 patients, and 19–24 per cent in a fourth patient. Serial measurements of chloride ion and comparison with animal experiments suggest that fetal respiratory tract fluid may contribute to amniotic fluid production in late human pregnancy.