Prevalence of beta group streptococcal colonization in rectovaginal discharge of pregnant women and comparison of maternal and neonatal complications in culture-treated individuals with those treated in risk factor at Arash Hospital.

Streptococcus beta group (GBS: Group B Streptococcus) is a gram-positive coccus that colonizes in the rectovaginal area. About 4.6% to 31.3% of women of childbearing age carry GBS infection. GBS colonization is a risk factor for subsequent infections in pregnant women that can be transmitted to the fetus through vertical transfer and aspiration of infected amniotic fluid. 2% of cases lead to an invasive infection in the baby. In most countries, treatment is done according to the CDC (Centers for Disease Control and Prevention) protocol which is based on culture results. According to studies conducted in our country, treatment is based on risk factors. Therefore, during this study, we decided to compare the results of treatment based on risk factors and treatment based on culture results and other maternal and neonatal complications in these two groups.

This case-control study was performed on 98 pregnant women aged 35 to 37 weeks who were referred to the perinatal clinic of Arash Hospital from April 2018 to the end of March 2020 and also 200 pregnant women with a GBS risk factor. Samples of rectovaginal discharge of 98 pregnant women were sent to a selected laboratory for culturing. In this group, treatment was performed based on the culture result. The control samples included 200 pregnant mothers who were treated based on risk factors without culture. Then the two groups were compared in terms of pregnancy outcomes.

Out of 98 subjects, 24 (24.5%) had positive rectovaginal culture. Individuals treated with antibiotics based on positive culture results did not show a significant difference in terms of observed pregnancy outcomes compared with the control group.

The prevalence of GBS colonization was significantly higher in patients with a history of vaginal discharge than in those without a history. Due to the small number of studies conducted in Iran, it is recommended to conduct studies with a larger sample size in order to explain a more appropriate protocol in terms of effectiveness and economics.