Predictive value of amniotic fluid lactate levels in parturients with simply decreased variation of fetal heart rate baseline in active phase for fetal stress

Objective To investigate the predictive value of amniotic fluid(AF)lactate levels in parturients with simply decreased fetal heart rate(FHR)baseline variation in active phase for fetal distress.Methods A total of 162 normal parturients admitted in out department with term singleton cephalic presentation fetus between May 2004 and September 2008 were enrolled in this study.Fetus cardiotocography were applied to everyone.Lactate level of amniotic fluid via vagina were examined in observation group(82 cases)while the control group(80 cases)received cardiotocography only.The cesarean rates,fetal distress rates of two groups were compared.Results The neonatal umbilical artery pH value at delivery and lactate level of amniotic fluid were negatively related(r=-0.752,P0.01).The lactate level of amniotic fluid in those with higher umbilical artery pH value(pH≥7.20)was significantly higher than those with lower umbilical artery pH(P0.05).The cesarean rate in research group(35.4%)was lower than the control one(52.5%)(P0.05).The incidence of umbilical artery pH value below 7.20 in research group was also lower(P0.05).Taking 8.9mmol/L as the upper normal borderline of amniotic lactate level,its sensitivity,specificity,positive predictive value and negative predictive value of fetal distress in parturients with simply decreased fetal heart rate(FHR)baseline variation were 82.3%,89.2%,67.0% and 95.1%,respectively.Conclusion AF lactate measurement may have some value for accurately diagnosing fetal distress in cases with decreased FHR baseline variation during active phase.