Is it suitable for DM diagnosis using an abnormal two-hour glucose value only after 24th gestational weeks in China

To investigate the postnatal outcomes of diabetes mellitus (DM) women diagnosed according to two-hour glucose value ≥11.1 mmol/L after 24th gestational weeks in China, and to evaluate if it is suitable for DM diagnosis using the criteria that two-hour glucose value ≥11.1 mmol/L after 24th gestational weeks only.Research design and methods: We conducted a retrospective cohort study of the pregnant women with gestational hyperglycemia participated in gestational hyperglycemia day care and delivered in Peking University First Hospital from June 2016 to May 2018. A total of 168 women diagnosed with DM according to the criteria that two-hour glucose value ≥11.1 mmol/L after 24th gestational weeks were included, and 75 DM women did the oral glucose tolerance test (OGTT) from 6 weeks to 1 year postpartum. The general information collected and analyzed included age, prepregnancy body mass index (BMI), prepregnancy weight, gestational weight gain (GWG), OGTT value during pregnancy, OGTT value of postpartum, gestational weeks, and neonatal birth weight.

There were 168 women diagnosed with DM according to the criteria that two-hour glucose value ≥11.1 mmol/L after 24th gestational weeks, and 75 (75/168, 44.6%) women underwent an OGTT from 6 weeks to 1 year postpartum. Among the women followed-up, 56 (56/75, 74.7%) women were diagnosed as hyperglycemia and 19 (19/75, 25.3%) women were diagnosed as normal glucose metabolism. In hyperglycemia women, there are eight (8/56, 10.7%) women diagnosed as DM, 24 (24/56, 32.0%) women diagnosed as impaired glucose tolerance (IGT), eight (8/56, 10.7%) women diagnosed as impaired fasting glucose (IFG), and 16 (16/56, 21.3%) women diagnosed as IFG and IGT. Compared with normal glucose metabolism women, the age of hyperglycemia women is higher significantly (34.8 ± 3.8 versus 32.7 ± 4.7). The incidence of IFG, pharmacy treatment, and the value of HbA1c is also higher in hyperglycemia women than the normal glucose metabolism women, in which it is not statistically significant but clinically significant.

In DM women diagnosed according to the criteria that two-hour glucose value ≥11.1 mmol/L after 24th gestational weeks, there were only eight (10.7%) women could meet DM diagnostic criteria according to the OGTT value of postpartum. Moreover, 25% women had normal OGTT value postpartum. Due to the characteristics of glucose metabolism in Asian population, an abnormal two-hour glucose value in OGTT may not be suitable to diagnose DM during pregnancy in China.