Objective: Measuring umbilical artery lactate levels to evaluating the predictive value of abnormal fetal heart rate (FHR) monitoring patterns for fetal distress.
Methods: There were 73 neonates with abnormal fetal heart monitoring patterns in the distress group. The abnormal patterns included abnormal baseline FHR, severe variable decelerations, mild variable decelerations and tachycardia. There were 118 normal neonates (Apgar score > or = 9) in the control group. Twenty min fetal heart monitoring was performed at the time of admitting, laboring and in labor and in active phase. Continuous fetal heart monitoring was performed during the second stage of labor. All neonatal umbilical artery lactate levels were measured at delivery.
Results: The rate of using forceps in distress group was significantly higher than that of the control (P < 0.01), the rate of spontaneous labor was significantly lower than the control group (P < 0.01). In the distress group, severe variable decelerations were generally emerged in the second stage of labor. The incidence of neonatal Apgar score < or = 7 in neonates with abnormal baseline FHR was higher than those with severe variable decelerations, mild variable decelerations and tachycardia (P < 0.05). As for neonatal umbilical artery lactate levels, the neonatatuses with abnormal baseline FHR was (4.55 +/- 0.23) mmol/L, the neonatatuses with severe variable decelerations was (3.84 +/- 0.40) mmol/L, all significantly higher than the control group's (P < 0.01). The neonatatuses with mild variable decelerations was (2.63 +/- 0.32) mmol/L, the neonatatuses with tachycardia was (2.55 +/- 0.46) mmol/L, and there are no significant differences between the neonatatuses with mild variable decelerations and tachycardia and the control group's (P > 0.05).
Conclusions: Measuring umbilical artery lactate levels is an efficient and accurate technique for fetal distress diagnosis. There was a close correlation between baseline FHR with abnormal changes and severe variable deceleration with fetal distress. There was no certainly correlation between mild variable decelerations and tachycardia with fetal distress. It should be evaluated later.