The spectrum of infections identified in pregnant women with different types of fetal growth restriction

BACKGROUND: Bacterial, viral and protozoal infections can cause miscarriage, antenatal death, congenital organ abnormalities or other limited consequences depending on the pathogen. The role of infection processes identified during pregnancy on placental pathology and fetal growth restriction.

AIM: The aim of this study was to conduct a comparative analysis of infections identified in pregnant women with different types of fetal growth restriction, as well as to assess a potential impact of identified infections on the outcomes of fetal growth restriction in newborns in the same groups.

MATERIALS AND METHODS: We performed a retrospective analysis of outcomes for 394 pregnant women with an established diagnosis of fetal growth restriction, who had given birth from 2018 to 2022 in the Perinatal Center of the Arkhangelsk Regional Clinical Hospital. Maternal and neonatal case histories were obtained using a continuous sampling method. Considering the transition to new criteria for establishing the diagnosis of fetal growth restriction in Russia, we formed four study groups, of which only 139 cases met the Delphi criteria of clinical guidelines by Russian Society of Obstetricians and Gynecologists, 2021. In the selected groups, we analyzed the results of microscopic and microbiological tests of various localizations in mothers during antepartum examination, as well as postpartum examination of the placenta and culture tests in newborns in their relation to adverse outcomes.

RESULTS: A high prevalence (25–70.4%) of positive bacteriological findings was revealed in all of the study groups. The frequency was highest in the group of pregnant women with fetal growth restriction before 32 weeks (90–92%). Combined infections (two or more localizations) were noted in 59.2% of pregnant women in groups with early fetal growth restriction compared to 23.3% in late fetal growth restriction groups. In all cases, we observed a direct relationship between the severity of fetal growth restriction and the prevalence of infections. The range of infections identified during routine examination of pregnant women is quite limited; Candida spp. (from 40.8% in the control group to 75% in the comparison group), Escherichia coli (from 22.9 to 33.3%, respectively), and Chlamydia trachomatis (from 4.5 to 23.5%, respectively) being identified most commonly. In a morphological study of the placenta, infectious and inflammatory lesions were the most significant and ranged from 100 to 81.4% of cases in groups with early and late fetal growth restriction, respectively, with signs of hematogenous transmission prevailed. When analyzing infectious lesions in fetuses, we have found the presence of three and more localizations of the infectious process in 90 to 45% of cases with a fatal outcome for early and late fetal growth restriction, respectively. In the control groups, similar rates were 40 and 15.8%. When assessing the distribution of various types of infectious process in newborns, Candida spp., Escherichia coli, and Enterococcus faecalis also took the lead in all cases. However, the percentage of the same etiology of maternal and neonatal infections turned out to be very low (from 0 to 31% for individual pathogens), which makes it difficult to apply preventive treatment during pregnancy.

CONCLUSIONS: Authors identified indirect but numerous signs of significant involvement of infectious processes in the development of fetal growth restriction, especially its early type, as well as the influence of infections on the outcomes for such newborns. In most cases, infectious processes during pregnancy are subclinical. Current screening of pregnant women is insufficient to identify high-risk groups. Examination of pregnant women for infections carried out by culture tests provide low-component and, most likely, incomplete information.