943 Abnormal glucose screening in an index pregnancy and gestational diabetes in a subsequent pregnancy

Abstract

In a non-diabetic pregnancy, the current practice is universal screening for gestational diabetes (GDM) using a 1-hour glucose challenge test (GCT) regardless of prior history. We aimed to determine whether an abnormal 1-hour GCT from an index pregnancy (PG1) can be used to guide GDM testing in a subsequent pregnancy (PG2). This was a retrospective cohort study of women who delivered 2 singleton pregnancies at >24 weeks from June 2009-December 2018 at a single institution. All patients had an abnormal PG1 GCT result (> 140 mg/dL). GDM was defined by GCT of >200mg/dL, >2 elevated values on a 3-hour diagnostic test (Carpenter-Coustan criteria), or a diagnosis by ICD codes. Univariable and multivariable analyses (MVA) were performed to examine the relationship between GDM in PG2 with variables from PG1. Given the high likelihood of GDM in subsequent pregnancies among women with GDM in PG1, the MVA was restricted to patients who were non-diabetic in PG1. 820 women met inclusion criteria, 356 (43.4%) had an abnormal 1-hour GCT in PG2, 233 (28.4%) developed GDM in PG2, and 48 (20.6%) of patients received a diagnosis of GDM without meeting laboratory criteria (Table 1). In MVA of subjects in a non-diabetic PG1, those with GDM in PG2 were significantly more likely to have higher GCTs in PG1, be of Asian race and have had gestational hypertension (gHTN) in PG1 (Table 2). In a non-diabetic PG1, the risk of GDM in PG2 increases with PG1 GCT result, Asian race and a history of gHTN. Of all patients with an abnormal PG1 GCT, regardless of PG1 diabetic status, 43.4% had an abnormal 1-hour GCT in PG2 with over a quarter of these patients diagnosed with GDM. Furthermore, our observation that 20.6% of patients diagnosed with GDM without laboratory criteria suggests that these women are considered at higher risk and are receiving the diagnosis of GDM regardless of diagnostic criteria. Thus, consideration can be given to supplant universal screening using a 1-hour GCT with direct diagnostic testing in women with a history of abnormal 1-hour screens in a prior pregnancy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)