Prevalence of hyperglycemia during pregnancy according to maternal age and pre-pregnancy body mass index in Japan, 2007–2009

ObjectiveTo assess the prevalence of hyperglycemia according to maternal age and pre-pregnancy body mass index (BMI) among Japanese women before introduction of the current diagnostic criteria.MethodsIn a retrospective study, data were analyzed from women with singleton pregnancies who were registered with the JSOG Successive Pregnancy Birth Registry System and who gave birth at 22 weeks of gestation or more between January 2007 and December 2009.ResultsAmong 138 530 women, 3667 (2.6%) were diagnosed with hyperglycemia including gestational diabetes and diabetes mellitus. The prevalence of hyperglycemia increased with advancing maternal age and increasing BMI. Among women aged ≤ 24, 25–34, 35–39, and ≥ 40 years, the prevalence was 0.4%, 0.8%, 1.5%, and 4.0%, respectively, in lean women (BMI < 18.5); 1.0%, 1.6%, 2.3%, and 3.1%, respectively, in normal weight women (BMI 18.5–24.9); and 5.7%, 9.2%, 12.9%, and 15.2%, respectively, in obese women (BMI ≥ 25.0). Of the 1181 newborns with a birth weight of 4000 g or more, 1046 (88.6%) were born to women not diagnosed with hyperglycemia.ConclusionThe results may reflect the baseline prevalence of hyperglycemia and macrosomic neonates (birth weight ≥ 4000 g) during the era of the old diagnostic criteria in Japan.