Diabetic Embryopathy
Incidence
Diabetes mellitus is a multifactorial disorder with a 5-10% risk for primary relatives (e.g., offspring of mothers with type I diabetes) to become affected with type I diabetes.
Clinical Characteristics
Infants of diabetic mothers (IDM) have increased risk for congenital malformation that correlates with the success of diabetic control during pregnancy. The malformation process and its resulting pattern of anomalies are referred to as diabetic embryopathy. In addition to fetal macrosomia and hypoglycemia, maternal diabetes mellitus can produce an embryopathy consisting of cranial, cardiac, and caudal anomalies (sacral agenesis, lower limb hypoplasia, urogenital anomalies). Of the 50 to 150,000 infants of diabetic mothers (IDM) that are born each year in the United States, those who experience problems with maternal diabetic control during gestation will have a 6-10% incidence of major congenital anomalies. These anomalies account for 50% of all deaths in the delivery and neonatal period. Although the classic IDM has a larger birth weight due to higher insulin levels, fetuses destined to develop congenital anomalies may exhibit a paradoxical growth delay. Major anomalies affecting the eye, jaw, heart, gastrointestinal tract, urinary tract, and central nervous system can occur in IDM. Underdevelopment of the tail end of the embryo (caudal regression) is the most characteristic anomaly of diabetic embryopathy, ranging from sacral agenesis (small sacral spine in the lower back) to sirenomelia (failure of the lower limbs to separate or "mermaid" anomaly). Caudal regression occurs in about 1% of IDM, necessitating orthopedic, urologic, and neurosurgical follow-up for severely affected children. The caudal underdevelopment may produce lower limb defects, urinary bladder dysfunction, and lower spinal cord anomalies such as tethered cord. Tethered cord involves fixation of the spinal cord to surrounding tissues, causing symptoms such as lower leg asymmetry, altered gait, or bed-wetting. Laboratory diagnosis is suggested by neonatal hypoglycemia, hypocalcemia, hypomagnesemia, and polycythemia.
Precipitants
No attacks but all IDM are at risk.
Provocation Tests
no
Diagnostic Procedures
The diagnosis of diabetic embryopathy depends upon alertness for typical anomalies in all IDM. Neonatal hypoglycemia, often associated with hypocalcemia, hypomagnesemia, and polycythemia.