Detection of subsequent episodes of gestational diabetes mellitus: a need for specific guidelines

Guidelines for detection of individuals with gestational diabetes mellitus (GDM) indicate that glucose testing for women with a history of GDM should occur as soon as feasible with retesting of an initially negative screen to occur between the 24th and 28th week of gestation. The aim of this study was to evaluate medical records for individuals enrolled in a GDM management program that presented with two subsequent pregnancies with GDM and to determine if more specific guidelines for detection are needed. Records (n=60) from both pregnancies were reviewed for gestational age at enrollment, delivery, and when insulin was started, infant birth weights and complications (e.g., hypoglycemia), and maternal complications (e.g., emergency cesarean section). Over half [33/60 (55%)] of the women required insulin during both pregnancies, while 16.7% (10/60) required insulin during the second enrollment for GDM but not the first. For those requiring insulin during both pregnancies, 88% (29/33) required it earlier during the subsequent pregnancy (31.5+/-2.7 vs. 21.6+/-8.4 weeks of gestation, P<.001). During the subsequent pregnancy, approximately 1/2 of the women requiring insulin needed it before the 24th week of gestation while 1/3 required it by the 15th week. Also during the subsequent pregnancy, neonate birth weights declined (3494+/-521 vs. 3356+/-515 g, P<.05) and there were fewer complications. Given that approximately 70% of the women required insulin therapy during a subsequent GDM pregnancy and that this therapy was on average necessary by the 22nd week of gestation, we recommend that specific guidelines be established with a definitive time frame determined for the detection of repeat episodes of GDM.