Subsequent pregnancy after gestational diabetes mellitus: frequency and risk factors for recurrence in Korean women

OBJECTIVE—The purpose of this study was to determine the frequency of recurrent gestational diabetes mellitus (GDM) and to find risk factors that can predict the recurrence of GDM in Korean women with previous GDM.RESEARCH DESIGN AND METHODS—We evaluated women who had GDM in an index pregnancy (1993–2001) and a subsequent pregnancy by 2003. An oral glucose tolerance test (OGTT) was performed during the index pregnancy and 2 months postpartum. The recurrence rate of GDM was assessed among 111 women who had a subsequent pregnancy. Multivariate logistic regression analysis was used to identify independent predictors of recurrent GDM.RESULTS—The frequency of recurrent GDM in subsequent pregnancies was 45.0% (95% CI 35.6–54.4%). Women with impaired fasting glucose and/or impaired glucose tolerance 2 months postpartum were at increased risk for recurrent GDM (relative risk 2.31, 95% CI 1.24–4.30). Higher BMI before the subsequent pregnancy (P = 0.024), higher fasting glucose concentration (P = 0.007) 2 months postpartum, and lower 1-h insulin concentration (P = 0.004) of the diagnostic OGTT in the index pregnancy were independent risk factors for recurrence of GDM in subsequent pregnancies.CONCLUSIONS—GDM recurred in nearly half of subsequent pregnancies in Korean women. Fasting glucose 2 months postpartum might be a clinically valuable predictor of recurrent GDM risk.Gestational diabetes mellitus (GDM) is defined as glucose intolerance of variable severity with onset or first recognition during pregnancy (1). GDM is associated with adverse outcomes of pregnancy such as preeclampsia, cesarean delivery, macrosomia, and birth trauma (1,2). Furthermore, women with GDM and their offspring are at increased risk for the development of diabetes later in life (3–5). Recently, a randomized clinical trial demonstrated that treatment of maternal hyperglycemia significantly reduced perinatal morbidity in GDM (6). If we could identify risk factors for recurrent GDM, we might possibly prevent its recurrence. It may also be possible to reduce perinatal morbidity by early diagnosis and optimal treatment of recurrent GDM during the subsequent pregnancy.The reported frequency of recurrent GDM varies widely, from 30 to 84%, depending on the ethnicity of the subjects and the diagnostic criteria used (7). Although one study reported the recurrence rate of GDM in Asian women (8), the sample size was small and widely used diagnostic criteria for GDM were not applied.Risk factors associated with recurrence of GDM have also varied among reported studies (7,9). In general, greater maternal age, obesity, degree of hyperglycemia in the index pregnancy, increased weight gain, and short interval between pregnancies were suggested to be associated with recurrent GDM (7–11). However, biochemical parameters, such as glucose and insulin levels during pregnancy and/or early postpartum, have not often been evaluated as risk factors for recurrence of GDM. It is recommended that women with GDM have a glucose tolerance test to reevaluate glycemic status at the first postpartum visit (12). We hypothesized that the early postpartum glucose concentration might provide important information for predicting risk of recurrence of GDM. In this study we evaluated the recurrence rate of GDM in Korean women and risk factors for its recurrence, including a postpartum oral glucose tolerance test (OGTT).