Preterm birth in women with diabetes mellitus

Hypothesis/aims of study. Diabetes mellitus (DM) is associated with an increased risk of obstetric complications, including preterm birth (PB). The incidence rate of PB in women with DM is higher than in the general population and amounts to 30–40%. Nevertheless, there are still open questions on the structure of PB, pharmacological approaches to its prevention and treatment, as well as the feasibility of prolonging the timing of glucocorticoid therapy to reduce perinatal morbidity and mortality. The objective of this study was to research the features of structure and clinical approaches in the case of PB in women with different types of DM, based on a literature review.

Study design, materials and methods. The study was performed using literature search, screening, data extraction, and analysis of publications collected in world databases such as MEDLINE, EMBASE, CNKI, and Cochrane.

Results. The rate of PB is the highest in women with pregestational DM: 21–30% in type 1 DM and 19–40% in type 2 DM. The incidence of PB in gestational DM (7–10%) is almost equal to the general population level (7–9%) and depends on the type of diabetes therapy: insulin — 16%, diet — 7%. Risk factors for PB in women with DM are poor glycaemic control, microvascular complications of DM, hypertension, obesity, infection, age, fetal macrosomia, polyhydramnios, and congenital malformations. Adequate glycemic control from early gestation is an important condition for PB prevention. The structure of PB in patients with pregestational DM changes due to an increase in both spontaneous and induced PB proportions. The most common indications for early delivery in DM are preeclampsia, premature placental abruption, impaired renal function in diabetic nephropathy, severe forms of carbohydrate metabolism disorders, diabetic fetopathy, and fetal distress. The risk of fetal respiratory distress syndrome in newborns of mothers with DM is higher than in the general population. The maturity of the lungs of a newborn may be insufficient, even in the case of term delivery. The use of antenatal corticosteroids is effective prophylaxis of respiratory disorders. However, these corticosteroids can increase the risk of neonatal hypoglycemia.

Conclusion. Despite the “term” weight and height, the newborn of a mother with DM may remain immature, therefore, delivery at term is recommended. The gestational age, until which it is advisable to prescribe corticosteroids for pregnant women with DM, and the mode of delivery in the case of PB, remain a matter of debate.