Immunoreactive trypsin level in fetoscopically-obtained cord sera of second trimester fetuses.

Immunoreactive trypsin (IRT) has been assayed in cord blood collection by fetoscopy from fetuses with estimated gestational ages of between 16-24 weeks. Eighty per cent of the specimens contained more than 5 ng/ml of IRT indicating pancreatic synthesis of trypsin by mid-term. A prenatal test for cystic fibrosis based on IRT estimation might be valid if the onset of pancreatic dysfunction associated with the disease also occurs at mid-trimester.