Fetal Heart Tracing Patterns and the Outcomes of Newborns With Meconium-Stained Amniotic Fluid

Objective To determine if the presence of meconium-stained amniotic fluid (MSAF) by itself or in combination with abnormal fetal heart tracing (FHT) (category II and III) is associated with poor neonatal outcomes in full-term newborns. Design/methods This is a retrospective cohort study. Cases included singleton and full-term neonates with MSAF. Cases were compared to matched controls (clear amniotic fluids) for the outcomes. SPSS (IBM SPSS Statistics for Windows, Version 22.0, Armonk, NY, USA) and SAS 9.4 (SAS Institute Inc., Cary, NC, USA) were used for data analysis. Results From 5512 deliveries, 210 cases (MSAF group) and 210 matched controls were identified. Cases and controls were similar in most maternal characteristics. Abnormal FHT was present in 43.2% of cases compared to 17.6% of controls (p<0.001). Low Apgar scores (<7) at one and five minutes were more common in the MSAF group (p=0.03 and 0.007, respectively). The neonatal intensive care unit (NICU) admission rate was also higher in the MSAF group (p=0.002). However, the mean hospital stay was similar in both groups (p=0.44). Twenty-two (10.5%) cases required resuscitation at birth compared to six (2.9%) controls (p=0.003). After applying the logistic regression model to adjust for the FHT pattern and Apgar scores at one minute, the association of MSAF with resuscitation lost significance. The factors associated with resuscitation requirement at birth were Apgar score at one minute (adjusted odds ratios (aOR) 4.1; 95% CI 2.8-5.1, p<0.001) and abnormal FHTs (aOR, 0.03; 95% CI 0.004-0.257, p=0.001). Conclusions Neonates born with MSAF were more likely to have abnormal FHT and require resuscitation at birth. However, after adjusting for confounding factors, abnormal FHT and one-minute Apgar scores were the only variables predictive of resuscitation needs at birth.