Objective: Our purpose was to investigate changes with gestation in fetal plasma interferon gamma concentration.
Study design: A cross-sectional study at the Harris Birthright Research Centre for Fetal Medicine, London, was performed. Enzyme-linked immunoassay was used to measure plasma concentration in 54 fetal blood samples obtained by cordocentesis or cardiocentesis at 12 to 37 weeks' gestation.
Results: The concentration of interferon gamma in fetal plasma decreased exponentially from a mean of 1.2 U/ml at 12 weeks' gestation to a mean of 0.5 U/ml at 37 weeks (r = 0.460, p < 0.001).
Conclusions: The presence of high levels of fetal interferon gamma in the first trimester suggests that it may play an important role in early fetal immunologic development. Furthermore, this study has established reference ranges for interferon gamma that may be of value in the prenatal diagnosis of congenital infection.