VAGINAL AND PLACENTAL MICROBIOME IN PREGNANT AND LABORING WOMEN WITH OBESITY AND GESTATIONAL DIABETES MELLITUS
Authors: Zhelezniakov O.Y. , Kudin I.D. , Lazurenko V.V. , Novikova I.V. , Kryzska O.V. 
Published: December 2024

Introduction. The microbiome of pregnant women has become a significant focus of scientific research. Understanding the vaginal and placental microbiome is particularly important in the pathogenesis of intrauterine infections, chorioamnionitis, and preterm birth. Therefore, studying the microbiota of the vagina, placenta, and amniotic fluid—key barriers against infectious agents—is crucial for reducing perinatal complications.
This study aims to investigate the vaginal and placental microbiota in pregnant and laboring women with obesity and gestational diabetes mellitus, with the goal of reducing pregnancy complications and perinatal morbidity.
Materials and Methods. The study was conducted in two stages. The first stage involved a bacteriological analysis of the vaginal microbiota in 1,794 pregnant women with clinical signs of colpitis, who were admitted to the Department of Pregnancy Pathology at the Regional Clinical Hospital for examination and subsequent delivery in 2023–2024. In the second stage, a bacteriological study of the vaginal and placental microbiota was carried out in 37 obese women in labor with gestational diabetes mellitus (GDM) (main group) and 20 pregnant women without somatic or obstetric pathology (control group).
Results and Discussion. An analysis of the vaginal microbiota in 1,794 pregnant women with colpitis revealed the following distribution of pathogens: Enterococcus faecalis (627 cases, 34.9%), Candida albicans (510 cases, 28.4%), Escherichia coli (288 cases, 16.1%), Staphylococcus aureus (68 cases, 3.8%), Klebsiella pneumoniae (53 cases, 2.95%), Staphylococcus epidermidis (51 cases, 2.8%), Streptococcus agalactiae (46 cases, 2.6%), and Staphylococcus haemolyticus (41 cases, 2.3%). The frequency of all other bacteria was less than 1%.
In the main group of pregnant women with GDM and obesity, who developed chorioamnionitis (29 cases, 78.4%), the vaginal microbiota revealed the following bacterial counts: Lactobacillus spp. at 5×1035 \times 10^35×103 CFU, Klebsiella pneumoniae at 10410^4104 CFU, Enterococcus faecalis at 10510^5105 CFU, and Candida albicans at 10710^7107 CFU. In the subgroup of women with intrauterine fetal infection (18 cases, 48.7%), Klebsiella pneumoniae was detected at 10510^5105 CFU.
Regarding the placental microbiome in the main group, the most common pathogens were Enterococcus faecalis (32.4%), Escherichia coli (27.2%), Staphylococcus aureus (8.1%), Burkholderia cepacia (8.1%), Klebsiella pneumoniae (5.4%), Staphylococcus haemolyticus (5.4%), Candida albicans (2.7%), Enterobacter cloacae (2.7%), Staphylococcus epidermidis (2.7%), Streptococcus agalactiae (2.7%), and Streptococcus parasanguinis (2.7%). No bacteria were detected in the placental microbiota of the control group.
Conclusions. The investigation of the vaginal and placental microbiomes in pregnant women with obesity and gestational diabetes mellitus reveals the extent of bacterial colonization and associated damage in these sites. This knowledge is essential for the timely detection and treatment of infectious lesions in both the mother and fetus, aiming to reduce perinatal complications. Importantly, the pathogens identified in the vaginal and placental microbiomes during chorioamnionitis and intrauterine fetal infection do not always coincide, emphasizing the need for further research in this field.