Proportion of Streptococcus agalactiae vertical transmission and associated risk factors among Ethiopian mother-newborn dyads, Northwest Ethiopia

Group B Streptococcus (GBS) vertical transmission causes fetal and neonatal colonization and diseases. However, there is scarcity of data in low-income countries including Ethiopia. We conducted a cross-sectional study on 98 GBS positive mothers, and their newborns to find proportion of vertical transmission. GBS was identified from swabs by using recommended methods and vertical transmission at birth was confirmed by the culture of body surface swabs of newborns within 30 minutes following birth. GBS positivity among swabbed specimens collected for other purposes was 160/1540 (10.4%); 98 were from 385 recto-vaginal swabs of pregnant women, and 62 were from 1,155 swabs of the 385 births. Of the 98 GBS positive cases, 62 newborns were GBS colonized with vertical transmission proportion of 63.3%(95% CI: 54.1–72.4%). We identified that the proportion of vertical transmission in this study was within the range of other many global studies, but higher than recently published data in Ethiopia. Maternal educational level, employment and lower ANC visit were significantly associated risk factors to GBS vertical transmission. Efforts need to be made to screen pregnant women during antenatal care and to provide IAP to GBS positive cases to reduce mother to newborn vertical transmission.