Second trimester amniotic fluid endothelin-1 concentrations and subsequent development of intrauterine growth restriction.

Objective: The purpose of this prospective study was to record endothelin-1 (ET-1) concentrations in the second trimester amniotic fluid and compare these values in women who developed intrauterine growth restriction (IUGR) later in pregnancy with those with uneventful pregnancies.

Methods: Amniotic fluid was retrieved by amniocentesis from 125 women in the second trimester of pregnancy. The levels of ET1 were measured by a sensitive and specific radioimmunoassay.

Results: From the 125 women included in the study 12 had pregnancies that later developed IUGR and 88 had uneventful pregnancies. The ET1 concentration was significantly higher (P<0.005) in women who later developed IUGR than in normal pregnancy (106 pg/ml versus 64.7 pg/ml).

Conclusions: The amniotic fluid concentration of ET1 is elevated by the second trimester in women who later develop IUGR.