Even with strict glycemic control, fetal and infant complications
persist. Congenital anomalies are more frequent in the diabetic versus
nondiabetic pregnancies. Macrosomia and the resulting birth injuries
occur 10 times more frequently in diabetic pregnancies. Electrolyte
abnormalities and the hyperviscosity syndrome can make management
in the neonatal period challenging for pediatricians. Commonly encountered
complications in the perinatal and neonatal period include intrauterine
fetal demise, macrosomia or intrauterine growth restriction, birth
trauma, perinatal depression, congenital anomalies, respiratory distress
syndrome, hypoglycemia, electrolyte abnormalities such as hypocalcemia
and hypomagnesemia, polycythemia and hyperviscosity syndrome, hyperbilirubinemia,
and cardiomyopathy. No single pathogenic mechanism has been identified
that can explain the diversity of problems encountered in the IDM. Nevertheless,
most researchers agree that many of the effects can be attributed
to maternal metabolic control. In 1977, the hypothesis of “hyperinsulinism” in
the IDM was proposed and recognized that maternal hyperglycemia
causes fetal hyperglycemia that results in fetal islet cell hypertrophy
and beta cell hyperplasia due to chronic fetal pancreas stimulation.4 Insulin,
an anabolic hormone, and the hyperinsulinemic state lead to visceromegaly and
macrosomia. At delivery, with the sudden loss of maternal glucose
supplies, hypoglycemia quickly ensues. However, this hypothesis does
not tell the whole story because birth weight is not always correlated
with mean maternal plasma glucose concentration.5 It
is likely that control of fetal growth and fetal glucose homeostasis
are multifactorial.