Methods~Study design:~A prospective study that will evaluate the rate of diagnosis of late GDM and clinical effect of performing a repeat OGTT beyond week 32 in women with obesity (BMI >30 kg/m2) and morbid obesity (BMI >35 kg/m2) for whom loading sugar was normal in the second trimester. The study will be carried out in the Mother and Fetus Unit at the Galilee Medical Center in Nahariya, Israel.~Study population:~Target population: women hospitalized in the Mother and Fetus Unit for various reasons, e.g., premature labor, amniotic fluid leakage, reduced fetal movements, following a car accident, etc.~Inclusion criteria:~Women with normal OGTT at weeks 24-28~Women with BMI >30 kg/m2~Exclusion criteria:~Twins~Fetal abnormalities~Women who received steroids within the preceding week We will invite women who meet the enrollment criteria to participate in the study, and perform an OGTT.~Research objectives:~Primary endpoints:~The percentage of obese women with late GDM diagnosis will be divided into two groups according to BMI:~BMI 30-35 kg/m2~BMI >35 kg/m2~Secondary endpoints:~Differences in the following obstetric outcomes between women diagnosed or not diagnosed with GDM: percentage of macrosomia, delivery method, shoulder dystocia, grade 3-4 tear~Differences in the following newborn outcomes between women diagnosed or not diagnosed with GDM: hypoglycemia, jaundice, need for phototherapy, polycythemia, hospitalization in neonatal intensive care, Apgar score, and newborn pH~Research procedure, interpretation of results, and patient follow-up:~The OGTT involves assessing fasting blood glucose, drinking a solution comprising 100 g of glucose, and three glucose tests at one, two, and three hours following glucose load.~Interpretation of the OGTT result is performed according to Carpenter-Coustan criteria [6]~Women who are not diagnosed with GDM will be discharged for continued follow-up for regular prenatal care and the reason for her hospitalization.~Per standard of care (regardless of research involvement) women diagnosed with GDM will receive counseling by a dietitian and other key department staff and undergo a complete glucose curve (seven tests per day: fasting, before each of three meals, and two hours after each meal).~If more than 30% of glucose tests are abnormal, the patient will receive standard drug treatment.~Follow-up is usually performed for 1-2 days in the hospital ward, after which women are discharged to ambulatory follow-up at the Mother and Fetus Clinic of the medical center.~Statistical analysis:~The sample size was calculated using the chi square formula for comparing two groups.~In a previous study in which repeat OGTT was performed beyond week 32 after initially normal results at week 24-28, the diagnosis rate of GDM for the total sample was 10%. An effect size of 20% was considered significant between obese and morbidly obese women with alpha=0.05, power 80%. The calculated sample size was 124 (at least 62 obese and 62 morbidly obese women).
In the current work, we aim to perform a prospective study that will investigate the relationship between maternal obesity (BMI >30 kg/m2) and morbid obesity (BMI >35 kg/m2) with a late GDM diagnosis (>32 weeks), with an emphasis on obstetric and neonatal outcomes.