Intrapartum Fetal Heart Rate Tracing Among Small-for-Gestational Age Compared With Appropriate-for-Gestational-Age Neonates

Abstract

Objective: To compare fetal heart rate (FHR) patterns during the last hour of labor between small- (SGA; birthweight <10th percentile for GA) and appropriate-for-gestational-age (AGA; birthweight at 10–90th percentile) neonates at ≥36 weeks of gestation. We also compared the rate of cesarean delivery and composite neonatal morbidity among SGA and AGA newborns. Methods: This is a secondary analysis of a randomized trial of intrapartum fetal ECG ST-segment analysis. We excluded women with chorioamnionitis, insufficient duration of FHR tracing in the hour before delivery, and anomalous newborns. Fetal heart rate patterns were categorized by computerized pattern recognition software (PeriCALM Patterns). Composite neonatal morbidity was defined as any of the following: intrapartum fetal death, Apgar score ≤3 at 5 minutes, cord artery pH ≤7.05 and base deficit ≥12 mmol/L, neonatal seizure, intubation at delivery, neonatal encephalopathy, neonatal death. Logistic regression was used to evaluate the association between FHR patterns and SGA adjusted for magnesium sulfate exposure and stage of labor. Results: Of the 11,108 women randomized, 85% (n=9,402) met inclusion criteria, of whom 9% were SGA. In the last hour, the likelihood of accelerations was significantly lower among SGA than AGA neonates (72.4% vs. 66.8%; P=0.001). Variable decelerations lasting >60 seconds, with depth >60 bpm or nadir <60 bpm were significantly more common with SGA than AGA (all P<0.001). The rate of late decelerations, prolonged decelerations, or bradycardia were similar between SGA and AGA (all P>0.05). Cesarean delivery for fetal indications was significantly more common with SGA (7.0%) than AGA (4.0%; P<0.001). The composite neonatal morbidity was 1.4% among SGA and 1.0% among AGA (OR 1.40; 95% CI 0.74, 2.64). Conclusions: Although the FHR patterns in the last hour of labor differ among SGA and AGA infants, as does the rate of cesarean delivery, the composite neonatal morbidity was similar.

Risk factors for Cesarean delivery in pregnancy with small‐for‐gestational‐age fetus undergoing induction of labor

“…suggested that this higher probability of NRFHT is due to lower oxygen reserves during labor in SGA fetuses. Recently, Chauhan et al . compared FHR patterns during the last hour of labor between SGA and appropriate‐for‐gestational‐age (AGA) fetuses at 36 weeks of gestation or later.…”

“…Parisi et al 25 suggested that this higher probability of NRFHT is due to lower oxygen reserves during labor in SGA fetuses. Recently, Chauhan et al 26 compared FHR patterns during the last hour of labor between SGA and appropriate-for-gestational-age (AGA) fetuses at 36 weeks of gestation or later. They found a significantly lower likelihood of accelerations and an increased likelihood of variable decelerations in SGA fetuses compared with in AGA fetuses.…”

Application of Prospect Theory in Obstetrics by Evaluating Mode of Delivery and Outcomes in Neonates Born Small or Appropriate for Gestational Age

“…Various international guidelines do not indicate cesarean delivery (CD) for fetuses with FGR; however, more obstetric interventions during labor and delivery are reported among these fetuses, with approximately 30% of fetuses with FGR estimated to be delivered via CD . In addition to the obvious detrimental associations of CD and operative vaginal deliveries with maternal morbidity, the neonatal benefit of CD in neonates with FGR remains unclear, and the optimal mode of delivery of neonates who are SGA remains to be determined …”

Trial of Labor After Cesarean of Small for Gestational Age Neonates Among Women with No Prior Vaginal Delivery — a Retrospective Study

“…Uteroplacental insufficiency is the most common etiology associated with fetal growth restriction [14]. Therefore, labor may pose a challenge for the compromised growth restricted fetus and possibly lead to fetal heart rate abnormalities [22,31,32]. This association is reflected by the fact that the indication for CD was non-reassuring fetal heart rate in more than three-quarters of cases in our study, substantially higher than previously reported data available on intrapartum CD indications, which have reported a rate ranging from 15.5 to 18.1% [33,34].…”