Objective. To assess the sufficiency of vitamin D (25 (OH) D) in mother-child dyads in type 1 diabetes mellitus (DM 1) in the autumn-winter-spring period.

Material and methods. A prospective study was carried out on the basis of the State Institution «Republican Scientific and Practical Center «Mother and Child». Pregnant women delivered at term of full-term fetus (n=128) in the period from October to May 2018—2021 were divided into 2 groups depending on the presence or absence of type 1 diabetes mellitus. Group 1 (Gr 1) included 72 women with diabetes mellitus, group 2 (Gr 2) — 56 pregnant women without diabetes. Vitamin D was determined in umbilical cord blood and in women in labor.

Results. The study revealed an insufficient content of 25 (OH) D in the mother-child dyads against the background of pregnancy with type 1 diabetes mellitus in the autumn-winter-spring period, corresponding to the deficit status. Hypovitaminosis D is diagnosed in the majority of pregnant women with diabetes mellitus 1 and their newborn children. Deficiency of 25 (OH) D was detected in 83.3% of pregnant women, insufficiency — in 15.3%. In the umbilical cord blood of newborns born to mothers with diabetes, deficiency of 25 (OH) D was observed in 86.1%, insufficiency — in 9.7%.
A statistically significant positive correlation was found between the levels of vitamin D in the mother-child dyads in the serum of women and the umbilical cord blood of their newborns (r=0.617, p<0.001 in Gr 1 and r=0.562, p<0.001 in Gr 2). In newborns of mothers born with large weight by gestational age, direct correlations were traced between the concentrations of 25 (OH) D in umbilical cord blood and blood serum of women (r=0.633, p=0.001 in Gr 1 and r=0.905, p=0.002 in Gr 2).

Conclusion. This study made it possible to establish the insufficient content of 25 (OH) D in the mother-child dyads against the background of pregnancy with type 1 diabetes mellitus in the autumn-winter-spring period.