Perinatal Outcomes in Gestational Diabetes in the Province Of Trento: A Study on Birth Cohorts 2017-2019

Piffer S, Rizzello R, Pedron M, Orrasch M, Zambotti F and Zardini S

Published on: 2023-02-07

Abstract

Introduction: Gestational diabetes (GDM) is a condition of carbohydrate intolerance that is diagnosed during the second or third trimester of pregnancy and whose development is favoured, especially in women with known risk factors, by the metabolic modifications induced by pregnancy.This retrospective observational study reports the prevalence of GDM in pregnant women assisted at maternity units in the Province of Trento (North East Italy) in the years 2017-2019. The study also analyses the obstetric and neonatal outcomes on the basis of the data provided by the Birth Assistance Certificate (BAC).

Material & Methods: The diagnostic criteria for GDM used are those of the International Association of Diabetes and Pregnancy Study Group (IADPSG).The monitoring data during pregnancy are recorded in the Birth Assistance Certificate (BAC), a mandatory document in Italy for monitoring pregnancy, childbirth and health of the newborn. Prevalence of GDM was analyzed, on the basis of the data recorded in the BAC. The characteristics of pregnant women with GDM were evaluated compared to pregnant women with normal glucose tolerance. The evolution of pregnancy and obstetric outcomes were analyzed for the two subpopulations of pregnant women. The characteristics of infants of mothers affected by GDM compared to those of mothers with normal glucose tolerance were analyzed. Differences in obstetric-neonatal outcomes between GDM mothers and mothers with normal glucose tolerance were finally analyzed on the basis of a multiple analysis according to the logistic model. The possible effect modifications of some maternal characteristics were also evaluated.

Results: During the study period, 12,401 pregnant women were assisted at the maternity units in the Province of Trento. A total of 841 cases of GDM were recorded (280 cases/year), 480 of whom were Italian and 361 foreigners. The average period prevalence of GDM among all of the pregnant women was 6.8 % (95%CI 6.3-7.2) among Italian women 5.2 % (4.8–5.4) and among foreign women, 11.4 % (10.4–12.4).  Pregnant women with GDM have, compared with those in the normal glucose tolerance (NGT group), an older age, a higher proportion of multiparous and less educated pregnant women, about twice the prevalence of foreign women and overweight women, and an approximately four-fold prevalence of obesity. Pregnant women with GDM present, in pregnancy, compared to NGT pregnant group a double proportion of hypertension/eclampsia/preeclampsia, a more frequent recourse to induction of labor and caesarean delivery, especially elective, a greater frequency of vaginal tears, in the case of vaginal delivery. Infants born to GDM mothers compared to those born to NGT group have an excess of preterm deliveries, low birth weight, LGA and macrosomes. Likewise, there is an excess of newborns hospitalized at birth, subjected to resuscitation and phototherapy. The multivariate analysis, conducted only on singleton pregnancies, indicates which neonatal events associated with the GDM status of the mothers, an excess of elective and labor cesarean deliveries and an excess of newborns hospitalized at birth. The mother's age and prepregnancy BMI influence the use of elective cesarean delivery.

Discussion: The BAC, if properly used, allows an epidemiological representation of the GDM in the reference population. Pregnant women with GDM have different socio-demographic characteristics compared to NGT pregnant women. Pregnancy assistance for the former is not dissimilar to NGT pregnant women. Compared to the latter, they present an excess of preeclampsia and a greater use of caesarean delivery. The more frequent recourse to cesarean delivery, especially elective, reduces the cases of shoulder dystocia at delivery. More frequent use of cesarean section and hospitalization at birth represent the only significantly different adverse effects in those born to mothers with GDM.