Amniotic Fluid L-Type Fatty Acid-Binding Protein in Predicting Fetal Condition.

Ultrasonography and fetal heart rate monitoring are subjective assessments of fetal condition, which warrants the need for objective markers to predict fetal condition. Urinary L-type fatty acid-binding protein (L-FABP) levels correlate with hypoperfusion. Elevated amniotic fluid L-FABP levels may represent fetal tissue hypoperfusion since the amniotic fluid contains fetal urine. In this study, we aimed to analyze the effectiveness of amniotic fluid L-FABP as a predictor of fetal condition. We classified singleton pregnancies into groups based on fetal growth restriction (FGR) with and without fetal blood flow abnormalities (FGR and healthy-FGR groups, respectively) and the non-FGR group (control group). We collected amniotic fluid at the time of vaginal delivery, cesarean section and amniocentesis, and compared the patient characteristics, clinical outcomes and amniotic fluid levels of L-FABP between the groups. We analyzed 153 singleton pregnancies and 186 amniotic fluid samples (FGR group, 6 (3.9%) pregnancies and 23 (12.4%) samples; healthy-FGR group, 15 (9.8%) pregnancies and 20 (10.7%) samples; control group, 132 (86.3%) pregnancies and 143 (76.9%) samples). The amniotic fluid L-FABP level was significantly higher in the FGR group compared to that in the healthy-FGR and control groups. Multivariate analysis revealed that the amniotic fluid L-FABP level was not affected by fetal body weight. Additionally, the amniotic fluid L-FABP levels increased significantly in cases with fetal blood flow abnormalities or early gestational age. Therefore, amniotic fluid L-FABP level may be an objective and accurate predictive marker of fetal condition.