Patterns of congenital anomalies and relationship to initial maternal fasting glucose levels in pregnancies complicated by type 2 and gestational diabetes

OBJECTIVES: We sought to determine the types of congenital anomalies affect ing infants of women with gestational diabetes mellitus or type 2 diabetes and to examine the relationship between those malformation types and measur es of initial glycemia of women at entry into prenatal care with type 2 dia betes or at time of diagnosis in women with gestational diabetes mellitus. STUDY DESIGN: A total of 4180 pregnancies complicated by gestational diabet es mellitus (n = 3764) or type 2 diabetes (n = 416) that were delivered aft er 20 weeks of gestation were reviewed for the presence of congenital malfo rmations diagnosed before hospital discharge. Anomalies were categorized as being absent, minor, major, genetic syndromes, or aneuploidies. Major anom alies were further categorized by the number and type of affected organ sys tems. In addition to maternal clinical and historical parameters, the initi al fasting serum glucose either from the diagnostic glucose tolerance test (gestational diabetes mellitus) or at entry to prenatal care (type 2 diabet es) and the initial glycosylated hemoglobin before insulin therapy were exa mined for a relationship to anomalies. RESULTS: The initial fasting serum glucose and glycosylated hemoglobin leve ls were significantly higher in pregnancies with major (n = 143) and minor (n = 112) anomalies and genetic syndromes (n = 9) compared with pregnancies with no anomalies (n = 3895). Of those pregnancies with major anomalies, t he most commonly affected organ systems were the cardiac (37.6%), musculosk eletal (14.7%), and central nervous systems (9.8%) and anomalies involving multiple organ systems (16%). There was no increased predominance of any sp ecific organ system involvement seen with increasing fasting serum glucose levels in pregnancies with major congenital anomalies. Pregnancies with maj or anomalies affecting multiple organ systems had significantly higher init ial fasting serum glucose levels (166 +/- 64 mg/dL) compared with pregnanci es in which one organ system was affected (141 +/- 55 mg/dL, P<.04) or no o rgan systems were affected (115 +/- 38 mg/dL, P<.0001). CONCLUSION: Congenital anomalies in offspring of women with gestational and type 2 diabetes affect the same organ systems that have been previously de scribed in pregnancies complicated by type 1 diabetes. Increasing hyperglyc emia at diagnosis or presentation for care was associated with an increasin g risk of anomalies in general and with anomalies involving multiple organ systems without a preferential increase in involvement of specific organ sy stem.