You are called to the operating room to manage an infant recently born by emergency cesarean delivery. The mother, an 18-year-old with one previous child, received no prenatal care and arrived at the hospital approximately an hour prior to delivery. At delivery you find a large (4500 g), grayish-colored infant with poor tone, no spontaneous respirations, and a pulse of 100 beats per minute (bpm).
What is the first step in the evaluation of this child?
What is the most likely diagnosis?
What is the next step in evaluation?
ANSWERS TO CASE 18: Infant of a Diabetic Mother
Summary: A very large newborn with respiratory depression.
• First step: Resuscitation of the infant focuses on the ABCs: A (airway), B (breathing), and C (circulation). Oxygen is provided, and the infant is stimulated to breathe on his own. If these simple measures fail, bag-and-mask ventilation and endotracheal intubation may be required. Upon oxygenation, the infant’s poor tone, color, and slow heart rate should resolve.
• Most likely diagnosis: Respiratory distress in an infant of a diabetic mother (IDM).
• Next step: Once the infant’s cardiorespiratory status is stabilized, frequent checks for hypoglycemia over the next 24 hours are indicated.
1. Recognize the clinical features of the IDM.
2. Know the management of the IDM.
3. Know the infant anomalies that are associated with pregestational diabetes.
Fetal hyperinsulinism is a response to poorly controlled maternal hyperglycemia resulting in fetal macrosomia and increased fetal oxygen requirements. These two factors can make the birth process difficult and result in neonatal distress.
After delivery and removal from the high-sugar in utero environment, the infant’s hyperinsulinism can cause hypoglycemiaand must be managed immediately to prevent further complications. A blood glucose level of 25 to 40 mg/dL requires immediate feeding. A level less than 25 mg/dL (or higher levels in symptomatic infants) is treated with intravenous glucose.
Respiratory distress syndrome, polycythemia with hyperviscosity syndrome, hypocalcemia, hypomagnesemia, and hyperbilirubinemia are other sequelae of gestational diabetes that may require management.
Infant of a Diabetic Mother
GESTATIONAL DIABETES: Persistent hyperglycemia during pregnancy, with serum glucose levels greater than 95 mg/dL in the fasting state and above the thresholds for the oral glucose tolerance test.
HYPOGLYCEMIA: A blood glucose level less than 40 mg/dL is the usual definition, although other definitions exist. Symptoms include lethargy, listlessness, poor feeding, temperature instability, apnea, cyanosis, jitteriness, tremors, seizure activity, and respiratory distress.
MACROSOMIA: Larger than normal baby with the birth weight exceeding the 90th percentile for gestational age, or any birth weight >4 kg.
POLYCYTHEMIA:In a newborn, a central hematocrit >65. This can lead to thrombosis if the infant is symptomatic and remains untreated.
CAUDAL REGRESSION SYNDROME: Rare congenital malformation found almost exclusively in the IDM, characterized by hypoplasia of the sacrum and lower extremities.
Diabetes affects an average of 7% of pregnancies. For most women, the condition is transient, occurring during pregnancy and disappearing after delivery. Women are screened for gestational diabetes (GDM) between 24 and 28 weeks of pregnancy (but can be screened earlier if considered high risk). It is classified according to maternal age when the condition is first diagnosed (onset during gestation, or pregestational), the duration of symptoms, and the presence of vasculopathy (the “White Classification”). Women who require insulin therapy are at higher risk for a poor perinatal outcome than those whose carbohydrate intolerance can be managed by diet alone. Women with preexisting diabetes are followed closely; many of the congenital malformations associated with gestational diabetes are thought to result from hyperglycemia early in the pregnancy.
The fetal pancreas begins producing insulin during the fourth month of gestation and becomes functionally significant after week 26, when macrosomia due to maternal hyperglycemia may first be noted. Increased infant weight and length occur because of increased adipose tissue deposition and the growth hormone effects of insulin. Increased glycogen is stored in the infant liver, kidney, skeletal muscle, and heart. Height and head circumference are less significantly affected because insulin does not affect bone and brain growth. Thus, the weight of an IDM typically is in its shoulders and abdomen.
Macrosomia, increased oxygen requirements, and placental insufficiency can lead to perinatal asphyxia and increased production of erythropoietin. The resultant polycythemia contributes to elevated bilirubin levels and can cause hyperviscosity syndrome with resultant venous thromboses (kidney, sinus), stroke, necrotizing enterocolitis, or persistent pulmonary hypertension. Hypocalcemia is common and results in irritability, sweating, or seizures.
Infants of a diabetic mother are at increased risk for congenital malformations, including congenital heart disease, neural tube defects, small left colon syndrome,and the caudal regression syndrome. Their large size at birth can complicate vaginal delivery; shoulder dystocia is a common problem in the vaginal delivery of a large IDM. Conversely, an IDM may be small for gestational age if the mother’s diabetes is associated with severe vascular disease and resultant placental insufficiency. IDMs may be small in infancy but are often overweight in childhood and adolescence.
18.1 A 35-week-gestation infant is delivered via cesarean section because of macrosomia and fetal distress. The mother has class D pregestational diabetes (insulin-dependent, with vascular disease); her hemoglobin A1c is 20% (normal 8%). This infant is at risk for birth asphyxia, cardiac septal hypertrophy, polycythemia, and which of the following?
A. Congenital dislocated hip
C. Hyaline membrane disease
18.2 A term infant weighing 4530 g is born without complication to a mother with class A pregestational diabetes (non-insulin requiring). His initial glucose level is 30 mg/dL, but the level after he consumes 30 cc of infant formula is 50 mg/dL, and another level obtained 30 minutes later is 55 mg/dL. His physical examination is unremarkable except for his large size. Approximately 48 hours later, he appears mildly jaundiced. Vital signs are stable, and he is eating well. Which of the following serum laboratory tests are most likely to help you evaluate this infant’s jaundice?
A. Total protein, serum albumin, and liver transaminases
B. Total and direct bilirubin, liver transaminases, and a hepatitis panel
C. Total bilirubin and a hematocrit
D. Total bilirubin and a complete blood count
E. Total and direct bilirubin and a complete blood count with differential and platelets
18.3 A premature infant of a class B pregestational (insulin-requiring, but without vascular disease) diabetic mother is delivered via cesarean section due to fetal distress. The mother’s axillary temperature at delivery is 98.6°F (37°C). The child has poor color and tone, no spontaneous cry, minimal respiratory effort, and a weak pulse of 80 bpm. After endotracheal intubation, the color and tone improve a bit, but she still has perioral cyanosis and her heart rate is 90 bpm. Which of the following is the most likely cause of her persistent distress?
C. Impaired cardiac function
D. Renal failure
18.4 A term girl born to a mother with class C pregestational diabetes (insulin-dependent, but without vascular disease) requires endotracheal intubation at delivery for poor respiratory effort, tone, and color. Her initial serum glucose level is 10 mg/dL, and the level stabilizes over 36 hours with intravenous administration of glucose. She is extubated and begins to breastfeed. On the third day of life, she has been feeding every 3 hours and voided twice; physical examination is remarkable for macrosomia, plethora, and a new abdominal mass. Which of the following is the most likely cause of the abdominal mass?
B. Infarction of the spleen
C. Small left colon syndrome
D. Liver engorgement
E. Renal vein thrombosis
18.1 C. Infants born to mothers with poorly controlled diabetes are at risk for respiratory distress syndrome (surfactant deficiency) at later gestational ages than seen in infants born to mothers who do not have diabetes.
18.2 C. This baby most likely has hyperbilirubinemia secondary to liver immaturity, possibly complicated by polycythemia. He should have a high level of unconjugated bilirubin and, in the absence of intrahepatic disease, a normal conjugated (or direct) portion. While choices D and E include the correct answer, additional tests are unnecessary for this otherwise healthy-appearing infant who continues to feed well. Therefore, C is the best answer to the question.
18.3 C. Infants born to mothers with poorly controlled gestational diabetes are at risk for congenital heart anomalies, hypertrophic cardiomyopathy, septal hypertrophy, conotruncal anomalies, and subaortic stenosis. This child’s symptoms and the maternal diabetes history indicate a risk for cardiac problems. Sepsis can cause similar symptoms, but no risk factors for infectious disease are noted. This child is at risk for hypoglycemia, but hypoglycemia alone would less likely explain all of her symptoms.
18.4 E. Renal vein thrombosis can present as an abdominal mass because the kidney becomes congested and palpable. The other classic components of its presentation, gross hematuria and thrombocytopenia, are seen in 25% of patients. Many patients will be oliguric. Hypertension is uncommon following an acute thrombosis but may occur as a late complication. Hydronephrosis is a common cause of abdominal or flank masses in neonates but is not the most likely given this infant’s accompanying history. Small left colon syndrome presents with failure to pass meconium in the first 2 days of life with resultant abdominal distention and vomiting.
Infants of diabetic mothers are at risk for perinatal complications, including hypoglycemia, hyperbilirubinemia, birth trauma, and congenital malformations.
Infants of diabetic mothers usually are heavier and longer than expected, but head circumference usually is normal. Infants of diabetic mothers can be small for gestational age if placental insufficiency is present.
Routine prenatal care includes screening for gestational diabetes.
American Diabetes Association. Standards of medical care in diabetes–2010. Diabetes Care. 2010; 33(1): S15.
Bernstein D. Evaluation of the cardiovascular system: history and physical examination. In: Kliegman RM, Stanton BF, St. Geme III J, Schor N, Behrman R, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: WB Saunders; 2011:1531t.
Carlo WA. Infants of diabetic mothers. In: Kliegman RM, Stanton BF, St. Geme III J, Schor N, Behrman R, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: WB Saunders; 2011:627-629.
Densmore JC, Oldham KT. Abdominal masses. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:1392-1393.
French HM, Simmons RA. Infant of a diabetic mother. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:195-198.
Journeycake JM, Chan AKC. Diagnosis and management of thrombosis. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:1579.
Warshaw JB, Hay WW. Infant of the diabetic mother. In: McMillan JA, Feigin RD, DeAngelis CD, Jones MD, eds. Oski’s Pediatrics: Principles and Practice. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:423-427.