Features of lymphocyte subset composition in neonates born to mothers suffered from COVID-19 at different stages of pregnancy

The relationship between the incidence of COVID-19 in pregnant women who have had a coronavirus infection at different gestational ages and the health status of paired neonates is of great interest. However, no sufficient convincing data fully reflecting features of subsequent neonatal period, the state of the immune system in this category of children, affecting characteristics of postnatal period have been accumulated. Based on this, it underlies the relevance of the current study aimed at investigating parameters of clinical and immunological state of neonatal health after paired mothers recovered from COVID-19 at different gestational ages. The prospective study included 131 women and 132 children. The main group consisted of women (n = 61) who had COVID-19 during pregnancy and paired newborns (n = 62) at gestational age (GA) of 37–41 weeks, the comparison group — women without laboratory-confirmed COVID-19 during pregnancy (n = 70) and paired newborns (n = 70) of similar gestational age. While analyzing the anamnesis of the patients, no significant differences in somatic and obstetric-gynecological diseases were found. Analyzing course of pregnancy revealed that low molecular weight heparins were significantly more often applied in the main group. The term and frequency of delivery by caesarean section in pregnant women in the main group did not significant differ from that of the control group. No significant difference in the frequency of causes accounting for the severity of the condition of neonates in paired mothers with COVID-19 at different trimester of gestation was found. Investigating lymphocyte subset composition, neutrophil phagocytic activity, and IgG class antibodies specific to SARS-CoV-2 was carried out. It was found that lymphocyte subset profile in newborns from paired mothers with COVID-19 at different trimesters of gestation differed only in the level of NK cells (CD56⁺) in children born to mothers recovered from COVID-19 in the first trimester. In this study, in general, no severe perinatal outcomes in newborns from paired mothers with COVID-19 during pregnancy were documented. No cases of moderate or severe maternal COVID-19 were observed. Therefore, further prospective studies are needed to assess an impact of COVID-19 severity on maternal and fetal birth outcomes and clarify optimal management of pregnant women in such cases.