Untreated women with first trimester fasting glycaemia 92-125 mg/dL and risk of gestational diabetes mellitus in the 24-28th week OGTT: prevalence and predictors.

Abstract

Introduction: Women with first trimester fasting glycaemia (FTFG) 92-125 mg/dL may present with normal 24-28th week OGTT (2T-OGTT). Predictors of persistent hyperglycaemia were scarcely investigated. We studied the prevalence and predictors of gestational diabetes mellitus (GDM) in the 2T-OGTT in women with untreated elevated FTFG.

Methods: Retrospective study of women from the national GDM registry with FTFG between 92 and 125 mg/dL that had passed unnoticed and untreated until the 2T-OGTT.

Primary endpoint: GDM in the 2T-OGTT. Women with and without GDM were compared. A multivariate logistic regression analysis was used to study GDM predictors. Included variables: FTFG, newborn sex, and known GDM risk factors.

Results: We studied 407 women. 82% (82.1%) of women had a positive 2T-OGTT. Women with abnormal 2T-OGTT were older, had higher BMI, and more often carried female newborns. There were no differences concerning other known GDM risk factors, FTFG, and obstetric or neonatal complications. Age, BMI and newborn sex were associated with higher risk of GDM independently of other GDM risk factors or FTFG. Per 1 year of age and 1 kg/m2 of BMI, the OR (95%CI) for this association were 1.10 (1.05-1.16) and 1.07 (1.02-1.12), respectively. Alternatively, women older than 35 years or with a BMI ≥ 30Kg/m2 had an OR of 2.53 (1.30-4.90) and 2.20 (1.22-3.98), respectively. Women with male newborns had approximately half the risk of abnormal 2T-OGTT [OR 0.51 (0.30-0.87)].

Conclusions: Nearly 18% of women with FTFG between 92 and 125 mg/dL had a normal 2T-OGTT. Older age, higher BMI, and female newborns were associated with increased risk of abnormal 2T-OGTT.