The authors estimated the number of live births worldwide with hyperglycemia in pregnancy. The prevalence of hyperglycemia in pregnancy in women (20 to 49 years) is 16.9%, or 21.4 million live births. An estimated 16% may be due to total diabetes in pregnancy. The highest prevalence was found in the South-East Asia Region at 25% compared with 10.4% in the North America and Caribbean Region. More than 90% of cases of hyperglycemia in pregnancy are estimated to occur in low- and middle-income countries.