Ethnic-specific oral glucose tolerance (OGTT) phenotypes in women with hyperglycemia in pregnancy.

Introduction: Ethnic differences associated with oral glucose tolerance test (OGTT) phenotypes is less studied in Southeast Asian ethnicities, especially in women with hyperglycemia in pregnancy (HIP).

Research design and methods: We retrospectively examined 3027 women at KK Women's and Children's Hospital in 2019. Of these, 508 (16.8%) women were diagnosed with HIP using the IADPSG (International Association of Diabetes and Pregnancy Study Groups) criteria at 24-28 weeks. OGTT phenotypes were classified into four mutually exclusive groups based on abnormal plasma glucose at (1) 0 hour only; (2) 1 hour only; (3) 2 hour only; (4) ≥2 timepoints (reference). Multinomial logistic regression was used to examine the association between ethnicity and OGTT phenotypes, adjusting for maternal age, parity, and first-trimester body mass index.

Results: Overall HIP prevalence was 16.8%, highest among Indians (20.5%), then Chinese (18.3%) and Malays (14.2%). Indians (relative risk ratio (RRR) 3.05) and Chinese (RRR 2.33) were at higher risk of displaying a fasting-only phenotype compared with Malays. Chinese were at increased risk of displaying a 2-hour postprandial phenotype with an RRR of 2.88 as compared with Malays.

Conclusions: Unique OGTT phenotypes exist across ethnic groups among women who developed HIP in a multi-ethnic Asian population.