Deceleration area of FHR and fetal academia at delivery: a case-control study.

Objective To determine the ability of a new parameter, the deceleration area of fetal heart rate to identify a fetal acidemia at delivery in physiologic pregnancies. Study design We have analysed the deceleration area of FHR recording in 56 women during the last hour preceding delivery. All the pregnancies progressed to term without any problem and did not require induction of labor. Twentyeight pregnancies with fetuses presenting an acidemia condition at delivery and 28 pregnancies with foetuses without any alteration of the emogas-analysis at birth as controls. Deceleration area was calculated, after digital analysis, with Autocad System 2004 with FHR from 140 to 120 bpm. Umbilical artery cord blood was collected at birth and immediately placed on ice. The blood gases were determined within 5 minutes of collection from the umbilical artery. Results were expressed as mean ± SD. Unpaired Student´s t-Test was used to compare results, statistical significance was set at p < 0.05. Results We have identified a significant statistical correlation in the control group about the number of decelerations (p < 0.001), and about deceleration area calculated at 140 bpm, at 130 bpm and 120 bpm, for the last 60 and 30 minutes before delivery (p < 0.001). Conclusion We have demonstrated that the analysis of decelerations is useful to identify a fetal distress and that the area of those decelerations is a sensible and refined parameter to foretell a fetal acidemia at delivery.