171-LB: Evaluation of Universal Diabetes Diagnostic Testing at First Prenatal Visit

Diabetes mellitus (DM) in pregnancy is not routinely screened for in Haiti. If done, screening relies on OGTT at 24-28 weeks (w) of gestation. It is unclear whether this is an optimal approach in Haiti. We aimed to evaluate the implications of a universal DM diagnostic testing before 24 w.

All consecutive pregnant women aged ≥18 y without known DM attending their first pregnancy visit in 4 prenatal clinics of Port-au-Prince and surroundings were invited to participate. Using a Contour Next^R glucometer, eligible subjects underwent: Fasting blood glucose (FBG) test at 1-23 w and ≥36 w, 75g 2-h OGTT at 24-28 w for FBG <126 mg/dL before 24 w or at 24-35 w-first visit. We used WHO/IADPSG diagnostic criteria for DM in pregnancy (DIP) (FBG ≥126 mg/dL and/or 2h ≥200 mg/dL) and for gestational DM (GDM) (1 or more: FBG 92-125 mg/dL, 1-h BG ≥180 mg/dL, 2-h BG 153-199 mg/dL).

A total of 945 women (mean age 29.78 ± 5.77 y, parity 2.04 ± 1.29, pre-eclampsia: 3.80%, caesarian section: 18.75%, preterm birth: 7.13%, single or living alone: 10.13%, family history of DM: 10.11%) were studied. Women with first visit at < and ≥24 w were 332 and 613, respectively. Prevalence of DIP and GDM by first screening period was: 7.20% and 13.02% overall, 12.35% and 13.86% at <24 w, and 4.40% and 12.56% at ≥24 w. Median FBG progressively decreased from 83 mg/dL at ≤5 w to 73 mg/dL at ≥36 w, p=0.0000. Of the 40 women with GDM at <24 w, 20 had GDM confirmed and 20 were normal on OGTT. A cut-off value of FBG >100 mg/dL at <24 w for DM (DIP and GDM) diagnosis on OGTT had: specificity (SP) 98.8%, sensitivity (SE) 19.3%, and positive predictive value (PPV) 78.6%. A cut-off value of FBG <72 mg/dL at <24 w to rule out DM on OGTT had: SP 12.2%, SE 98.3%, and NPV 96.8%. Women with these cut-offs represented 14.9% of those undergoing OGTT after the <24 w screening.

Our findings suggest that universal screening for DM before 24 w of gestation leads to diagnosis of DM in about 20% of pregnant women. A rule in/rule out approach using FBG <72 mg/dL and >100 mg/dL values at <24 w can help reduce the number of OGTT at ≥24 w.