Alphafetoprotein levels in amniotic fluid from 8 to 18 weeks of pregnancy.

Objective: The aim of this study was to ascertain the normal range of amniotic fluid alphafetoprotein (AFP) levels from 8 to 18 weeks of pregnancy.

Design: Amniotic fluid samples obtained by amniocentesis were analysed by radioimmunoassay for AFP. From 8 to 12 weeks, fluid was obtained by transvaginal amniocentesis prior to termination of pregnancy.

Early amniocentesis: alphafetoprotein levels in amniotic fluid, extraembryonic coelomic fluid and maternal serum between 8 and 13 weeks.

Objective: The aim was to establish a normal range of alphafetoprotein (AFP) concentrations in amniotic fluid from 8 to 12 weeks gestation, and to determine any difference between AFP levels in amniotic fluid and extraembryonic coelomic fluid.

Design And Subjects: 150 women had a transvaginal ultrasound guided amniocentesis before termination of an apparently normal first trimester pregnancy. Separately identified samples of amniotic fluid and extraembryonic coelomic fluid were obtained and assayed by radioimmunoassay for AFP.

Human chorionic gonadotrophin and alpha-fetoprotein levels in matched samples of amniotic fluid, extraembryonic coelomic fluid, and maternal serum in the first trimester of pregnancy.

Separately identified samples of amniotic fluid and extraembryonic coelomic fluid obtained by high resolution transvaginal ultrasound-guided amniocentesis from 32 women between 7 and 12 weeks of pregnancy were analysed for human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP). There was a highly significant difference between the hCG levels in amniotic fluid (median level 6.3 U/ml; range 1.