Purpose: The 2010 recommendations of the Centers for Disease Control and Prevention (CDC) for prevention of perinatal group B Streptococcal Disease (GBS) is that symptomatic newborns suspect for early onset sepsis (EOS), or newborns born to mothers with clinical chorioamnionitis should receive antibiotic treatment. Our protocol was changed accordingly during 2015. We prospectively assessed the safety of the protocol and evaluated the need to treat all newborns born to mothers with clinical chorioamnionitis and retrospectively evaluated the performance of the EOS risk calculator.
Methods: The study period was from May 2015 to April 2016 at the Kaplan Medical Center (KMC). Inclusion criteria were: gestational age of 35 weeks and above, newborns that were treated with antibiotic, newborn born to mothers with risk factors for EOS or with maternal clinical chorioamnionitis, or to mothers that were given intra-partum antibiotic prophylaxis (IAP).
Results: In the study period, 7058 newborns were born, 1341 (19%) neonates were included according to the inclusion criteria. Six newborns had EOS (0.85 per 1000 live born). 123/1341 (9%) of the neonates were symptomatic of whom six (4.9%) had proven EOS with RR 10.9 (CI 3.5-33.39, p < .0001), NNT was 22.6. Of them, 89/1341 (6.6%) were treated for maternal clinical chorioamnionitis, two (2.25%) had proven EOS, but they were also symptomatic. The RR was 5.03 (CI 1.03-24.6 p = .045) and the NNT was 55.5. Symptomatic newborns were at an increased risk of 2.2 to have EOS compared with newborns with maternal clinical chorioamnionitis. During the study period, 201 (15%) newborns received antibiotic treatment, while if we had only used the calculator, 111 (8%) newborns would have been treated (p<.001). Only one (out of three with maternal risk factors) newborn was symptomatic during the first hour of life. Three of the mothers whose newborn developed EOS, had no risk factors so there was no need for the calculator. The calculated EOS risk at birth for the other three ranged from 0.37 to 0.67.
Conclusions: We suggest that asymptomatic newborns born to mothers with clinical chorioamnionitis should not receive antibiotic treatment automatically.
Keywords: Chorioamnionitis; early onset sepsis; intra partum antibiotic treatment.