Infections remain the leading cause of infant mortality: among premature infants, infections account for 57–67% of deaths. The actual number may be higher than official statistics, as such infants are sometimes registered as stillborn or as fetuses lost in late miscarriages.
Between 2016 and 2018, the number of newborns in Russia with extremely low birth weight (500–999 g) increased. Reducing mortality among infants born at very early gestational ages directly affects overall infant mortality rates.
All this underscores the need to study risk factors for preterm birth and develop infection prevention strategies.
At early stages, fetal development depends on the macro- and microenvironment before and after conception. As pregnancy progresses, the placenta becomes the central organ of protection. Structural and functional placental disorders are considered major causes of prematurity.
Women who give birth prematurely frequently exhibit ascending placental infection, primarily choriodeciduitis and intervillositis. These conditions lead to chronic placental insufficiency. Most commonly, infections are bacterial or mixed bacterial–viral.
Russian researchers conducted a comparative analysis of placentas from cases of early neonatal death in infants born at 24–27 and 28–32 weeks of gestation with extremely low and very low birth weight:
- Group 1 – 48 placentas at 24–27 weeks
- Group 2 – 31 placentas at 28–32 weeks
Primary Causes of Early Neonatal Mortality in Infants With Extremely Low and Very Low Birth Weight
In newborns with extremely low birth weight, the leading causes of death were:
- 2% – nontraumatic grade II–III intraventricular hemorrhages
- 7% – congenital viral–bacterial pneumonia
- 4% – generalized viral infection
- 4% – hyaline membrane disease (neonatal respiratory distress syndrome)
- 3% – early neonatal sepsis
In 32.3% of cases, hemorrhages occurred together with congenital pneumonia.
In newborns with very low birth weight, the main causes of death were:
- 2% – congenital pneumonia
- 7% – nontraumatic intraventricular hemorrhages
- 4% – generalized viral infection
- 3% – neonatal sepsis
Morphological Features of Placentas in Preterm Birth
In both groups, placental mass, volume, and maternal surface area were reduced. Hypoplasia was more pronounced in the 28–32-week group.
Inflammatory changes dominated the placental pathology pattern. In the 24–27-week group, chorioamnionitis and deciduitis were diagnosed more frequently. Placentas of newborns with very low birth weight were characterized by chronic inflammation. Inflammatory processes were accompanied by impaired villous chorion maturation.
Polymerase chain reaction identified:
- Herpetic infection – in 33.4% of cases in Group 1 and 23.4% in Group 2
- Chlamydial infection – in 22.1% and 26.3% of cases in Groups 1 and 2, respectively
Circulatory Disorders in Placentas in Preterm Birth
Maternal and fetal circulatory disorders were more frequently detected in placentas of newborns with very low birth weight. The incidence of placental abruption did not differ significantly between groups.
In placentas at 28–32 weeks, fetal circulatory disorders were more common: ischemic infarctions, as well as chronic maternal blood flow abnormalities. In placentas at 24–27 weeks, ischemic infarctions were less frequent, but thrombosis of the intervillous space occurred significantly more often.
Key Causes of Preterm Birth and Infant Mortality
Early neonatal mortality in infants with extremely low and very low birth weight was primarily caused by intrauterine pneumonia combined with intracranial hemorrhages.
Preterm birth was associated with placental insufficiency, primarily of infectious origin. Acute and chronic inflammatory processes were observed in placentas from both groups.
The Role of ARVI Prevention in Preventing Placental Disorders
According to the scientific literature, sources of intrauterine infection may include acute respiratory viral infection (ARVI) during pregnancy, chronic endometritis of viral or mixed etiology, and possible viral infection of sperm, with subsequent transmission to the trophoblast. These factors often coincide, making it impossible to determine the exact source of infection. Therefore, prevention and treatment of ARVI, as well as viral and bacterial sexually transmitted diseases, are essential during preconception care.
Intranasal recombinant interferon α-2b (IFNα-2b) preparations have demonstrated effectiveness and safety in pregnant women for seasonal and emergency ARVI prevention. IFNα-2b is effective against a broad spectrum of respiratory viruses – corona-, rhino-, and adenoviruses, influenza and parainfluenza viruses – and acts at the level of the nasal mucosa. Use of interferon α-2b from the first days of illness in the first trimester reduces the likelihood of placental disorders, fetal growth restriction, and decreases neonatal morbidity.
Prevention and Treatment of Infections During Preconception Care
During preconception planning, timely diagnosis and treatment of chronic reproductive tract infections and prevention of sexually transmitted infections (STIs) are essential. Combined preparations containing metronidazole, fluconazole, and interferon α-2b are used to treat dysbiotic and infectious–inflammatory disorders. These preparations are active against viruses, bacteria, protozoa, and fungi and are used for bacterial vaginosis and nonspecific or mixed vaginitis. For cutaneous and mucosal manifestations of herpes infection, preparations containing acyclovir and IFNα-2b are used.
Conclusion
Changes in the placentas of premature newborns are most often associated with chronic and acute infectious and inflammatory processes, accompanied by impaired villous chorion maturation and maternal and fetal circulatory disorders. Therefore, prevention and treatment of STIs during preconception care, as well as ARVI prevention during pregnancy, are essential for preventing placental disorders, fetal growth restriction, and reducing neonatal morbidity. Intranasal recombinant interferon IFNα-2b has demonstrated effectiveness and safety from the first days of ARVI in the first trimester. Combined preparations containing metronidazole, fluconazole, acyclovir, and IFNα-2b may be used to treat reproductive system infections.
