A newborn girl is evaluated in the delivery room 30 minutes after delivery. The infant was born at 41 weeks gestation to a 23-year-old woman, gravida 2 para 1, via uncomplicated vaginal delivery. The mother was previously healthy and had routine prenatal care. Serology was normal. The pregnancy was complicated by polyhydramnios and gestational diabetes necessitating insulin. The infant's vital signs are normal and birth weight is 4.2 kg (9 lb 4 oz). Apgar scores were 7 and 9 at 1 and 5 minutes, respectively. Physical examination shows an active, crying infant lying under the radiant warmer. Cardiac auscultation reveals a soft, 1/6 systolic murmur. The infant's hands and feet are cyanotic; the mucosal membranes are pink. Moro reflex is normal. The remainder of the examination is normal. Which of the following tests is most likely to be abnormal?

Question

A newborn girl is evaluated in the delivery room 30 minutes after delivery.  The infant was born at 41 weeks gestation to a 23-year-old woman, gravida 2 para 1, via uncomplicated vaginal delivery.  The mother was previously healthy and had routine prenatal care.  Serology was normal.  The pregnancy was complicated by polyhydramnios and gestational diabetes necessitating insulin.  The infant's vital signs are normal and birth weight is 4.2 kg (9 lb 4 oz).  Apgar scores were 7 and 9 at 1 and 5 minutes, respectively.  Physical examination shows an active, crying infant lying under the radiant warmer.  Cardiac auscultation reveals a soft, 1/6 systolic murmur.  The infant's hands and feet are cyanotic; the mucosal membranes are pink.  Moro reflex is normal.  The remainder of the examination is normal.  Which of the following tests is most likely to be abnormal?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d662_352e_bc81_4d03ae1ed235_MD0003_00 Infants of diabetic mothers (IDMs) are at increased risk for a variety of complications. Because glucose is actively transported across the placenta to the fetus, excessive maternal hyperglycemia leads to fetal hyperglycemia. The effects of fetal hyperglycemia vary depending on the developmental stage of the fetus: First trimester: The fetus cannot produce insulin during the first trimester and therefore cannot protect itself from hyperglycemia. Hyperglycemia during the first trimester can disrupt organogenesis, resulting in malformations (eg, congenital heart disease). Infants whose mothers have gestational diabetes are not at increased risk for malformations because maternal/fetal hyperglycemia does not develop until after organogenesis is complete. Second and third trimesters: Once the fetal pancreas is sufficiently developed, hyperglycemia triggers the release of insulin, which results in increased glycogen and fat storage (organomegaly), increased growth factor production (macrosomia, or birth weight ≥4 kg [8 lb 13 oz]), and increased oxygen consumption (polycythemia). IDMs who are macrosomic are more difficult to deliver vaginally, leading to higher rates of cesarean delivery (due to failure to progress) and operative vaginal delivery (eg, forceps, vacuum); clavicle fractures, brachial plexus injuries, and asphyxia are associated with macrosomia. After delivery, fetal insulin production takes time to decrease whereas maternal glucose exposure ends as soon as the umbilical cord is clamped. This often results in a period of neonatal hypoglycemia until insulin levels normalize. Hypoglycemia is the most common complication among IDMs. (Choice A) Risk factors for neonatal sepsis include maternal colonization with group B Streptococcus, prolonged rupture of membranes, and chorioamnionitis. IDMs are not at increased risk for sepsis, which would be very unlikely in this well-appearing infant with a normal examination. (Choice B) Risk for clavicle fracture is increased in macrosomic infants such as this patient. However, the normal Moro reflex makes clavicle fracture unlikely. (Choice C) Infants exposed to hyperglycemia in the first trimester as a result of poorly controlled, prepregnancy diabetes are at higher risk for congenital malformations, including microcolon (diagnosed with contrast enema). However, this mother had gestational rather than prepregnancy diabetes, so this infant is not at increased risk for congenital malformations. (Choice E) Risk factors for congenital hearing loss include congenital cytomegalovirus infection and family history of hearing loss. IDMs are not at increased risk for hearing loss, although this infant should receive hearing screening as recommended for all newborns. (Choice F) Hyperglycemia in the first trimester is associated with congenital heart disease, which may cause cyanosis. However, this mother had gestational rather than prepregnancy diabetes. This infant has acrocyanosis, or cyanosis of the hands and feet due to benign peripheral vasospasm. Acrocyanosis is a normal finding in newborns, and pulse oximetry shows normal oxygen saturation levels. Educational objective: Fetal hyperglycemia during the first trimester is associated with malformations; fetal hyperglycemia after the first trimester is associated with perinatal complications such as macrosomia, birth injury, and hypoglycemia. Neonatal hypoglycemia is the most common complication among infants of diabetic mothers. References: Care of the infant of the diabetic mother. (http://www.ncbi.nlm.nih.gov/pubmed/22094826)

A Newborn Girl Is Evaluated in the Delivery Room 30