Safety of Internal Electronic Fetal Heart Rate Monitoring During Labor.

Objective: To investigate the safety and efficacy of internal electronic fetal heart rate (FHR) monitoring during labor. Methods: This was a retrospective case-control study, which was an analysis of monitoring FHR with a fetal scalp electrode or a Doppler probe (94 pregnant women per group). In the internal monitoring group, when the opening of the uterine orifice was ≥3 cm, the fetal scalp electrode was placed after natural or artificial rupture of the membrane. FHR was simultaneously monitored using a Doppler probe. In the external monitoring group, continuous FHR monitoring was performed using an ultrasound Doppler transducer fixed on the maternal abdomen. The toco transducer was used to record uterine contractions. Pathological examination of the placenta was performed prospectively in 49 and 48 cases in the internal electronic FHR monitoring group and control group, respectively. Maternal-infant outcomes (e.g. fever, puerperal infection, puerperal morbidity, delivery mode, Apgar score, and scalp injury) were recorded. Umbilical artery blood was extracted for blood gas analysis. Differences between the two groups were compared using the paired Results: Non-statistically significant differences between the internal and external monitoring groups were observed in the incidence of neonatal acidosis (1/94 (1.06%) Conclusion: Internal FHR monitoring during labor does not increase the incidence of adverse perinatal outcomes. External monitoring was associated with FHR false decelerations.