Thermodilution measurement of human umbilical blood flow at delivery.

A local thermal dilution technique was used to estimate blood flow in the human umbilical vein during the first minute after delivery of the neonate. Estimates of flow were attempted at 101 deliveries and thermal dilution curves obtained at 52. The mean estimation of all flows recorded up to 20 seconds after delivery was 171 ml. per minute reducing to 58 ml. per minute between 40 and 60 seconds.