Results
A total of 127 women were treated for PPROM in our institution during the study time period. Of these, 106 women met inclusion criteria and were included in analysis (Table 1). All of our patients completed at least one course of betamethasone prior to delivery. Among these, 48 (45%) screened positive with the FMF fetal growth chart and 22 (21%) screened positive for SGA by the Hadlock method (RR 7.6 95%CI: 2.4 -24.3; p < .001). SGA was diagnosed in 12 infants (11%). Both fetal growth charts were statistically significant predictors of SGA, Hadlock: AUC = .76, RR 7.6 95%CI: 2.5- 23; p < .001, FMF: AUC: .76 RR 1.8-13.3 95% CI: 1.8 – 99.3; p = < .001. The diagnostic accuracy for SGA of the Hadlock fetal growth chart was similar to the FMF fetal growth chart (Figure 3). The sensitivity, specificity, positive and negative predictive values are presented in Table 2. Four SGA neonates were missed with the Hadlock fetal growth chart, and only one SGA was missed with the FMF fetal growth chart.
For our secondary outcomes, FGR by the Hadlock and FMF fetal growth chart had similar poor prediction ability for the composite of severe neonatal outcomes (Hadlock: AUC: .51, RR: .84 95%CI: .5-1.6 vs. FMF: ROC: .56 RR: 1.6 95%CI: .7-3.5; p = .23) (Figure 3). SNO complicated only two of the 12 SGA infants (17%) vs. 40 (42%) of the infants with appropriate weight for gestational age (AGA); RR .4 95% CI: .1-1.4; p = .012. Both of the SGA infants with SNO had RDS and one was also diagnosed with NEC.
SGA would have been diagnosed in 39% of our participant when both the fetal and neonatal FMF growth charts vs. 11% utilizing the Alexander birthweight growth chart (RR= 3.3 95% CI: 2.3-4: p = < .001). The FMF fetal chart was a statistically significant predictor of SGA defined by the FMF neonatal standard (AUC: .74, RR: 3.5 95% CI: 2- 6.2; p = < .001), but the FMF neonatal standard was not accurate predictor for the composite of neonatal outcomes (AUC: .56 RR:1.3 95%CI: .8-2.1; p = .23). The sensitivity, specificity, positive, and negative predictive value accuracy of the FMF standards are presented in Table 2.