Clinical and microbiological changes during pregnancy in women with congenital heart defects

Background: Cardiological pathologies, including heart defects, remain a leading cause of maternal mortality. Patients with congenital heart defects (CHD) have an increased risk of developing gestational complications and dysbiotic disorders due to hypoxemia caused by reduced cardiac output. However, there are only a few studies on the vaginal microbiota in pregnant women with CHD. Aim: The aim of the study was to evaluate clinical changes during pregnancy and assess the species composition of the vaginal microbiota in pregnant women with CHD, depending on hemodynamic manifestations. Methods: This retrospective study included 276 pregnant women, who were divided into 2 groups. The main group consisted of pregnant women with CHD (n = 149), and the comparison group comprised healthy pregnant women (n = 127). The group of pregnant women with CHD was divided into 2 subgroups: the first consisted of pregnant women with CHD and manifestations of chronic heart failure (CHF) (n = 47), and the second comprised pregnant women with CHD without CHF (n = 102). The course of pregnancy and laboratory parameters were assessed using maternity health records. A cardiologist established diagnoses of CHD and CHF based on clinical and instrumental examination in accordance with approved diagnostic criteria. Results: Vaginal microbiota disorders more often complicate pregnancy in patients with CHD, with the frequency of bacterial vaginosis positively correlating with the presence of CHF. In pregnant women with CHD, regardless of the presence of CHF, Staphylococcus spp., Candida spp., Enterococcus faecalis, and Escherichia coli were predominant in the vaginal microbiota. Candida spp. and E. coli were more common in pregnant women with CHD and CHF, leading to a higher miscarriage rate and urinary tract infections in this category of pregnant women. Conclusion: In pregnant women with CHD and CHF, Candida spp. and E. coli predominate in the vaginal biotope, while Lactobacillus spp. colonization decreases, leading to the development of gestational complications associated with infection. CHD combined with CHF in pregnant women is a risk factor for bacterial vaginosis.