Fetal heart rate patterns related to neonatal brain damage and neonatal death in placental abruption

The aim of this study was to determine the correlation between non-reassuring fetal heart rate (NRFHR) patterns and poor neonatal outcome in placental abruption.

A retrospective study was performed involving 83 placental abruptions with a live fetus at one tertiary and one secondary hospital in Miyazaki prefecture, Japan. We examined the correlation among NRFHR, umbilical arterial blood gas status, and neonatal poor outcomes, including neonatal death (ND) and cerebral palsy (CP).

A total of 83 cases were divided into bradycardia (n=27), recurrent late deceleration (rLD, n=29), severe variable deceleration or prolonged deceleration (sVD/PD, n=8), and other cases (n=19). In the bradycardia group, the incidence of low umbilical artery (UA) pH (<7.0) was 59% and the average UA pH was 6.96±0.22. Among these cases, 10 showed severe bradycardia (less than 80 b.p.m.) and an average UA pH of 6.85±0.24, and four cases resulted in poor outcome (three CP and one ND). In the rLD group, the incidence of low UA pH (<7.0) was 7% and the average UA pH was 7.24±0.12. In this group, a 40-week-old fetus with umbilical phlebitis had a lower UA pH (6.92) and developed CP. In the sVD/PD group, there were no cases of a low UA pH (<7.0) and the average UA pH was 7.30±0.04. In this group, a 31-week-old boy with a UA pH of 7.36 developed CP (PVL). The remaining 19 cases had no CP.

Poor neonatal outcome of placental abruption is closely related to NRFHR, especially the degree of bradycardia. In the rLD and sVD/PD groups, risk factors, such as prematurity and fetal inflammation, co-existed.