Incidence of neonatal sepsis among neonates between 28-36 weeks of gestation to mothers with varying duration of rupture of membrane

Sepsis is one of the most common causes of neonatal deaths globally (ref). The incidence of neonatal early onset sepsis has declined substantially over the last 2 decades, primarily because of the implementation of evidence based intrapartum antimicrobial therapy (ref). However neonatal sepsis remains a serious and potentially fatal illness (ref). The incidence of neonatal sepsis is 14.3 % and of culture positive sepsis is 6.2% in low and middle income countries like India (ref)(DeNIS trail).

Prolonged prelabour premature rupture of membranes (PPPROM) is rupture of amniotic membrane lasting for more than 18 hrs before onset of  labour in preterm gestation. Following PPPROM, approximately 50 % of women will deliver within one week.(ref). Majority of these infants born to women with PPPROM are exposed to risks associated with prematurity including respiratory distress syndrome (RDS), early onset sepsis (EOS), necrotizing enterocolitis (NEC), intraventricular haemorrhage (IVH), retinopathy of prematurity (ROP) as well as risks of cerebral palsy, blindness and deafness (ref).

Clinical chorioamnionitis has been reported to occur in 15 – 25% of pregnancies complicated by PPPROM, with subclinical infection being considerably more common (ref). Chorioamnionitis may present shortly after PPPROM and may result in preterm labor. Chorioamnionitis, diagnosed both clinically and histologically, was associated with early and late onset sepsis in neonates especially preterms (ref).

It is our unit practice to suspect sepsis in any preterm neonate born to mother with PPPROM of any duration and to initiate intravenous antibiotics emperically, though evidence has shown increased association of EOS with PPPROM>18 hours (ref). This is due to the fact that the incidence of EOS in these groups are relatively high in our set up. However, the evidence regarding the association of EOS with PPPROM of shorter duration is limited from low and middle income countries like India.

Given the fact that majority of preterm babies admitted in our NICU fall in the age group of 28-36 weeks gestation, we decided to prospectively observe the association of PPROM of any duration with EOS in preterm infants of 28 to 36 weeks gestation. Further we decided to compare the incidence of EOS in preterm infants born with rupture of membranes >18 hours with those born with rupture of membranes <18 hours.