Objective: To compare the incidences of early and late onset neonatal sepsis, including group B streptococcus (GBS) and Escherichia coli (E.coli) before and after implementation of universal screening. Design: Retrospective cohort study Setting: Eight public hospitals with obstetrics services under the Hospital Authority and 31 Maternal and Child Health Centres (MCHC) under the Department of Health in Hong Kong Population: 460552 women attending routine antenatal service from 2009 to 2020. Methods: Universal culture-based GBS screening was offered to eligible women since 2012. Total maternity, births, GBS screening tests, GBS isolated in maternal genital tract, neonatal sepsis with positive blood or cerebrospinal fluid were retrieved from clinical and laboratory database of the Hospital Authority using clinical data analysis and reporting system (CDARS) and clinical system of MCHCs. Main outcome measures: Maternal GBS colonisation rate, early onset GBS disease, early onset E. coli infection, late onset GBS disease, and late onset E. coli infection Results: Of 318740 women with universal culture-based screening, 63767 women (20.0%) were screened positive. After implementation of GBS screening, the incidences of both early and late onset neonatal sepsis reduced significantly, including those caused by GBS. There was no change in the incidence of early onset E.coli sepsis, while the incidence of late onset E.coli sepsis reduced. Conclusions: Universal culture-based GBS screening in Hong Kong has been successful in prevention of early and late onset neonatal sepsis, including those caused by GBS. E.coli has become more common than GBS in early neonatal sepsis, although the incidence remained similar.

Objectives: To assess whether adding placental growth factor (PlGF) or replacing pregnancy-associated plasma protein-A (PAPP-A) improves the first trimester combined test performance for trisomy 21. Design: Prospective observation Cohort Setting: The Chinese University of Hong Kong, China Sample: 11,518 women having a singleton pregnancy screened for trisomy 21 between December 2016 and December 2019 using the first trimester combined test. Methods: PlGF was prospectively measured and estimated term risk for trisomy 21 was calculated by 1) replacing PAPP-A with PlGF and 2) adding PlGF to the combined test which includes nuchal translucency, PAPP-A and free β-human chorionic gonadotropin (hCG). Main Outcome Measure: Screening performance, area under curve (AUC), detection rate (DR), screen positive rate (SPR) and false positive rate (FPR) Results: 29 women had trisomy 21. The combined tests DR, FPR and SPR were 89.7%, 5.7% and 6% respectively. DR when replacing PAPP-A or adding PlGF to the combined test remained unchanged. Replacing PAPP-A by PlGF increased FPR and SPR to 6.2% and 6.4% respectively. Adding PlGF to the combined test gave FPR and SPR rates of 5.5% and 5.7% respectively. Adding or replacing PlGF did not give a significant increase in AUC (p>0.48) over that of the combined test. Conclusion: Adding PlGF to the combined test or replacing PAPP-A with PlGF in the combined test did not improve trisomy 21 detection rate. Replacing PAPP-A by PlGF increased SPR, whilst adding PlGF resulted in only a marginal reduction in SPR.