RESULTS
During the study period, 196 women with PPROM between 28+0 to 33+6 weeks gestation were considered for study. Out of these, 66 had associated obstetric or medical conditions (preeclampsia, diabetes mellitus, intrahepatic cholestasis of pregnancy etc) and were thus excluded. Another 42 women went in spontaneous labor within 48 hours of admission and hence were not considered for study. Eight women declined to participate in the study and 10 women could not be evaluated within 48 hours of admission as shown in figure 1.
Out of 70 recruited patients with PPROM, 44 neonates were diagnosed with FIRS based on either raised IL-6 levels in cord blood or by presence of placental histologic features. Of these 44 neonates, all had raised IL-6 levels but only 16 patients had placental histologic features of FIRS. The overall prevalence of FIRS in cases of PPROM in our study was 62.86%. The mean IL-6 levels in the FIRS group was 77.37±74.51pg/ml whereas in the Non FIRS group it was 5.75±2.80pg/ml. Based on the presence of fetal inflammatory response syndrome, the study subjects were divided into the FIRS group and the Non FIRS group.
Both the groups were comparable with respect to maternal demographic parameters including age, education, parity, socioeconomic status. Maternal and neonatal descriptive characteristics for study participants are depicted in Table 1 which were found to be comparable between FIRS and Non FIRS group. The mean gestational age at the time of birth in the FIRS group was 32.78±1.23 weeks with a latency period of 8.77±7.94 days. These findings were comparable to the Non FIRS group where mean gestational age was 33.56±0.89 weeks and a latency period of 7.12±6.19 days. 75% of women in the FIRS group went in spontaneous labor and almost 80% women delivered vaginally. The mean birth weight was 1.59±0.269 kg in the FIRS group.
The Fetal urine production rate (FUPR) at time of delivery was significantly reduced in neonates who had evidence of FIRS at birth as compared to neonates without evidence of FIRS (13.89±8.06 ml/h vs 25.89±4.94ml/h). This association of FUPR with FIRS was found to be statistically highly significant with a p-value of <0.0001. Out of 41 patients with reduced FUPR prior to delivery, 39 babies were subsequently found to have FIRS while out of 29 patients with normal FUPR antenatally, only 5 babies had features suggestive FIRS (Table S1).
The mean IL-6 levels in patients with reduced FUPR was 67.21 ± 69.86pg/ml which was significantly higher as compared to 27.53 ± 60pg/ml in patients with normal FUPR. Neonates with reduced FUPR antenatally had significantly higher rates of severe neonatal morbidity, early neonatal sepsis, prolonged NICU stay and hospital stay shown in table 2 (58.54%,9.05 ± 7.52days, 12.83±8.50days). The neonatal mortality was 4.88% in neonates with reduced FUPR. The occurrence of RDS, NEC was significantly high in neonates with recued FUPR as compared to normal FUPR.
Out of 44 neonates in the FIRS group, 27 neonates (61.36%) had severe neonatal morbidity as compared to 8 neonates (30.77%) affected in the Non FIRS group. 27 babies had evidence of early onset neonatal sepsis in the FIRS group as compared to only 4 neonates in the Non FIRS group. Among the FIRS group, 15 (34.09%) neonates had RDS, 3 (6.82%) had NEC in comparison to the Non FIRS group where 4 (15.38%) had RDS and 1(3.85%) had NEC. Overall neonatal mortality was 4.55% belonging to FIRS group only (Table S2).
In our study, out of 70 patients with PPROM 42 had evidence of chorioamnionitis (clinical, bacteriological, histologic chorioamnionitis) making a prevalence of 60%. Of these 42 mothers having evidence of chorioamnionitis, 38 neonates had evidence FIRS while in the absence of chorioamnionitis, only 6 out of 28 neonates had evidence of FIRS. All the 16 patients with histologic feature of FIRS had features of chorioamnionitis also on placental histopathology while none of the patients showed features of FIRS in the absence of histopathological chorioamnionitis (Figure S1, Figure S2).
Table 3 shows correlation IL-6 levels and placental histopathological features of FIRS with neonatal outcomes, it was found that out of 16 patients who had raised IL-6 levels as well as histopathological features of FIRS, 15 (93.75%) neonates developed sepsis, 9 (56.25%) had RDS, 2 (12.5%) had NEC. In 28 cases with only raised IL-6 levels but no histologic evidence of FIRS, 12 (42.86%) neonates had sepsis, 6 (21.43%) developed RDS while 1 (3.57%) had NEC. In 26 patients with PPROM and no biochemical and histologic evidence of FIRS, only 7 (26.92%) neonates developed sepsis, 4 (15.38%) developed RDS.