What are clinical features of fetal macrosomia in gestational diabetes mellitus (GDM)?

Updated: Apr 29, 2020
  • Author: Thomas R Moore, MD; Chief Editor: George T Griffing, MD  more...
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The macrosomic fetus in diabetic pregnancy develops a unique pattern of overgrowth, involving central deposition of subcutaneous fat in the abdominal and interscapular areas. [39] Skeletal growth is largely unaffected.

Neonates of diabetic mothers have a larger shoulder and extremity circumference, a decreased head-to-shoulder ratio, significantly higher body fat, and thicker upper extremity skin folds compared with nondiabetic control infants of similar weights. Because fetal head size is not increased during poorly controlled diabetic pregnancy, but shoulder and abdominal girth can be markedly augmented, the risk of injury to the fetus after delivery of the head (eg, Erb palsy) is significantly increased. Thus, birth injury, including shoulder dystocia and brachial plexus trauma, are more common among infants of diabetic mothers, and macrosomic fetuses are at the highest risk.

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