Objective: to identify the diabetogenic type of the lateral behavioral profile of asymmetries, which reveals the highest incidence of GDM and obstetric complications in overweight pregnant women and, on its basis, to study the features of the somnological status in women with diabetogenic lateral constitution at the preconception period. Materials and methods: the study used special testing (Annette test, sleep quality questionnaire, sleep apnea/hypopnea syndrome questionnaire, sleepiness scale (Epworth)), polysomnographic study. Results: based on the results of a questionnaire survey and a polysomnographic study, somnological disorders were identified, expressed in a decrease in the efficiency and quality of sleep, fatigue, perceptible drowsiness in wakefulness, breathing disorders during sleep and other sleep disorders, which contributes to an increased risk of gestational diabetes mellitus mainly in women with an ambidextral lateral phenotype. Conclusion: the identified sleep disorders in overweight women in the pregravid period are, on the one hand, the result of hormonal changes against the background of already existing metabolic and vegetative abnormalities in overweight women planning pregnancy, on the other hand, they act as a “trigger” functional disorders both during the manifestation of GDM and during the formation of obstetric complications due to increasing hypoxemia in the maternal body against the background of the “obstructive sleep apnea” syndrome, which contributes to the development of fetal distress.