Predicting adverse maternal obstetric outcomes in pregestational diabetes mellitus with ultrasound, metabolic, and maternal demographic factors: a prospective cohort study

Abstract

BACKGROUND: Diabetes mellitus is a chronic disease that affects millions of individuals worldwide. Increasingly, it impacts women of reproductive age, posing additional challenges in many pregnancies and deliveries. Pregestational diabetes mellitus (PGDM) complicates approximately 1% of all pregnancies, representing a risk for both the mother and the fetus. Especially in cases of poor glycemic control, PGDM has been associated with congenital malformations, stillbirth, hypertensive disorders, macrosomia, and adverse obstetric events during vaginal delivery that include emergency cesarean sections, obstetric anal and sphincter injuries, postpartum hemorrhage, and even maternal death. A significant challenge in these pregnancies is the occurrence of macrosomic fetuses that present a particular body fat distribution, which can increase the risk of such obstetric complications. Therefore, the estimated fetal weight of a fetus is used to take different decisions regarding the type and timing of delivery. However, it has been observed that calculating this measure through ultrasound can be inaccurate, especially in fetuses of diabetic mothers. Consequently, it is relevant to investigate potential factors associated with maternal complications during childbirth which can help consider alternative delivery options and make well-informed decisions accordingly. OBJECTIVE: the main objective is to identify ultrasound, metabolic, and maternal factors that are associated with adverse maternal obstetric outcomes in women with PGDM. DESIGN AND SETTING: the study is designed as a multicenter observational prospective cohort. It will be carried out in the three main hospitals of the provinces of Girona, Lleida, and Tarragona. PARTICIPANTS AND METHODS: a total of 220 participants will be recruited for the study during the first ultrasound visit, including patients with known preexisting diabetes and those who obtained a positive screening result for PGDM during the first-trimester blood test. Patients with a clear indication for an elective cesarean section at the beginning or end of the pregnancy will be excluded. Patients will be followed throughout the course of pregnancy, collecting all necessary and relevant data until the moment of birth, where possible maternal complications during labor will also be documented