Introduction
What does IDM stand for? In the medical world, IDM is an acronym for Infant of Diabetic Mother. In this episode, we review the common complications associated with Infants of Diabetic Mothers. You may be surprised to hear that there are several complications beyond hypoglycemia or low blood sugars including but not limited to macrosomia, asphyxia, small for gestational age, respiratory distress, cardiac anomalies, neurological impairments, polycythemia, hyperbilirubinemia, hypocalcemia, and hypomagnesemia. Plus IDM infants are also at an increased risk for a preterm delivery and/or a cesarean section delivery due to their risk of complications later during the pregnancy or potentially larger size.
Not only will we break down the potential complications the IDM infant is at risk for one-by-one, but we also discuss the pathophysiology behind each diagnosis as well as the typical treatment plan for each complication.
If you are currently pregnant and have been diagnosed with gestational diabetes or had pre existing diabetes, this episode is for you! Or if you just had your baby and had diabetes with the pregnancy, this episode will provide you some great education.
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Episode 19
Infant of the Diabetic Mother
In our previous episode, we discussed Diabetes Mellitus, but more specifically gestational diabetes. We reviewed which women are at an increased risk to become diagnosed with gestational diabetes, how it is diagnosed, the general management, and how it affects the health of the mother and the fetus. If you have not already listened, I recommend that you go back and listen to Episode 18, Gestational Diabetes: From diagnosis in pregnancy to blood sugar management and its effect on the health of the mother and infant.
In episode 19, we dive more into the Infant of the Diabetic Mother and break down the complications that they are at an increased risk for one-by-one followed by how each complication is typically managed.
As I mentioned in our last episode, according to the CDC, each year gestational diabetes affects 2 to 10% of pregnancies in the United States.
Despite dramatic improvements in the last few decades in the management and care of the mother with either preexisting diabetes or gestational diabetes, risks still exist for the infant of the diabetic mother. With dietary management, oral medication, and insulin therapy, the morbidity and mortality rates for the infant of the diabetic mother have improved. Unfortunately though, complications still arise for the infant including hypoglycemia, hypocalcemia, hypomagnesemia, perinatal asphyxia, respiratory distress, hypertrophic cardiomyopathy, hyperbilirubinemia, polycythemia, macrosomia, birth injuries, and/or congenital malformations just to name a few! Due to the increased risk of complications in the IDM, these infants must be carefully evaluated.
As I mentioned in our last episode, maternal diabetic control is a key component in determining the outcome for the fetus and eventually the infant as the majority of the problems that occur in the infant of the diabetic mother are a direct result of fetal hyperglycemia and hyperinsulinism. Unfortunately, even with euglycemia or normal blood sugar levels during the pregnancy, the infant of the diabetic mother is still at risk for potential complications.
Now resuscitation efforts at the delivery for the infant of the diabetic mother do not differentiate from the typical Neonatal Resuscitation Program’s guidelines. The nurse, neonatologist, NNP, or Pediatrician attending the delivery should be made aware of the gestational diabetes diagnosis or if the mother had preexisting diabetes prior to the pregnancy.
Potential Complications of the IDM
Macrosomia
Infants of diabetic mothers are at an increased risk for macrosomia. Macrosomic infants are on the larger side with a weight of more than 4000 grams. The incidence of macrosomia in diabetic pregnancies is 45%. The infant’s large size is a result of the fetal hyperglycemia. The glucose from the mother crosses the placental, but the insulin does not. So the fetus produces an increased amount of insulin in response to the increased amount of glucose resulting in hyperinsulinemia.
Hyperinsulinemia causes accelerated secretion of insulin fetal growth hormones resulting in an increased amount of fat and glycogen stores in the liver. The elevated insulin levels may also cause an enlarged liver, spleen, and heart. Since macrosomia is due primarily to insulin stimulation of adipose or fat tissue, brain and head growth is normal resulting in a discoordinance between the head and shoulder size. IDM infants often appear chubbier than their counterparts of the same gestation. The acceleration of growth begins during the 25th to 28th week of pregnancy which is why very preterm infants of diabetic mothers are not typically larger.
With the infant being larger, it poses additional risks for the infant and mother at delivery. The infant is at an increased risk for shoulder dystocia leading to potential birth trauma including fractures of the clavicle and/or humerus. These infants are also at risk for birth asphyxia that has the potential to compromise either respiratory, renal, or central nervous system function. Brachial plexus injuries can also occur and lead to damage to the nerves of the arm. Mothers are also at risk for developing postpartum hemorrhage due to the difficult delivery.
Some mothers may also end up with a cesarean section or possibly early induction of labor if the obstetrician is concerned about the fetus’ size and the potential for delivery trauma for the mother and/or infant at delivery. An infant being delivered via cesarean section or those delivered early are also at an increased risk of additional complications.
Small for Gestational Age
On the other side of the spectrum, some infants may be smaller or small for gestational age meaning their birthweight is less than the 10th percentile. Maternal renovascular disease or a narrowing of the artery to one or both kidneys is a common cause of poor fetal growth in diabetic pregnancies resulting in suboptimal fetal growth. If the infant is small for gestational age, it also increases their risk for additional complications.
Cardiac Anomalies
There is also an increased risk of the fetus of a diabetic mother to develop congenital anomalies including cardiac defects. Thirty percent of infants of diabetic mothers present with septal hypertrophy, transposition of the great vessels, ventricular septal defect, atrial septal defect, and/or thickened myocardium. The septal hypertrophy occurs due to the higher levels of insulin in utero which makes the septum larger than normal. With septal hypertrophy, it increases the risk of heart failure and poor cardiac output after delivery. Cardiomegaly, or an enlarged heart, may appear on X-Ray and the infant may also present with respiratory distress and/or tachypnea. With these symptoms present, it often misleads the provider to believe that there are respiratory issues rather than cardiac. An echocardiogram or ultrasound of the baby’s heart can be done to determine if there are any cardiac anomalies.
Respiratory Distress
But, to make things even more complicated, the infant of a diabetic mother may also present with respiratory distress as well with retractions, grunting, and/or nasal flaring. The elevated insulin levels the fetus encounters in utero suppresses surfactant production and leads to immature lungs. If you’ve been an avid listener to our podcast, you’ll recall that we discussed surfactant and immature lungs in Episode 8, Take a Deep Breath – Diving Into Respiratory Distress Syndrome in Newborns.
Surfactant is a lipid-dense liquid that spreads like a thin layer or film over the alveoli (or tiny air sacs) in the lungs and ultimately helps to keep them open. It acts like a lubricant in between the air sacs so they do not stick together, and can remain open for effective breathing. But in the IDM infant, due to the suppression of surfactant in utero, they are more likely to experience respiratory distress.
Respiratory distress may also occur if there is an inaccurate assessment of gestational age due to the fetal macrosomia resulting in an inadvertent preterm delivery that is commonly associated with respiratory distress. Additionally, a cesarean delivery due to concern for fetal macrosomia places the infant at an increased risk of respiratory distress or transient tachypnea of the newborn (TTN) due to the lack of labor and slower clearance of fetal lung fluid. And as I previously stated, some mothers may be induced earlier around 36-37 weeks or earlier if the diabetes is not well-controlled and preterm and late preterm infants are at an increased risk for respiratory distress.
With any type of respiratory distress in the infant, supportive care is the treatment. If the infant needs respiratory support, they may be placed on a ventilator, CPAP, a HFNC, or a nasal cannula with supplemental oxygen as needed. If an X-Ray demonstrates features of respiratory distress syndrome and immature lungs, exogenous surfactant may also be given.
Neurological Impairments
Infants of diabetic mothers are also at an increased risk of neurologic impairments commonly resulting in immature sucking patterns. Due to their neurological immaturity, IDM babies are often labeled as poor feeders. An IDM’s lack of desire to suck can be very frustrating for parents. It is often presumed they will eat well especially if they are macrosomic or on the larger side. But, oftentimes they appear uninterested and/or exhausted. But do not give up and try to remain patient, they just may need a little bit of extra time and they’ll figure it out!
Hematologic Disorders
Polycythemia
Another common complication of the IDM infant are hematologic disorders including polycythemia or/or hyperbilirubinemia. Polycythemia is an increased number of red blood cells, but more specifically is defined as a hematocrit greater than 65% and is found in 20-40% of IDM infants in the first few days after birth. The certain pathogenesis remains uncertain, but is believed to be due to hypoxemia. The fetus endures hypoxemia or an abnormally low level of oxygen in the blood from the maternal hyperglycemia or elevated blood glucoses. The elevated maternal glucoses lead to elevated fetal blood glucoses and ultimately elevated fetal insulin levels. The cascading of events results in an increased metabolic rate and oxygen consumption as the baby’s body tries to metabolize the excess sugar.
With the hypoxemia in utero, the fetus produces more erythropoietin – a hormone that helps to make red blood cells. This occurs due to their attempt to increase the number of red blood cells since it is the red blood cells that transport oxygen. So, we end up with more red blood cells or polycythemia which leads to hyperviscosity or sluggish blood flow and eventually leads to hyperbilirubinemia or elevated jaundice levels.
Clinically, babies with polycythemia present as being ruddy or having more of reddish skin tone, with sluggish capillary refill, a faster respiratory rate, and possibly jitteriness and/or seizures. The cause and severity of the infant’s polycythemia determine the appropriate medical management. If the infant is feeding well and hydrated, the elevated hematocrit may be closely monitored and will naturally come down. If it is severe and/or if the infant is symptomatic, a partial exchange transfusion may need to be done which involves removal of the infant’s blood or red blood cells and replacing them with normal saline.
Hyperbilirubinemia
Now, unfortunately, if an infant is polycythemic, it also places them at an increased risk of developing elevated bilirubin levels or hyperbilirubinemia. The increased number of red blood cells results in more red blood cells break down which leads to elevated jaundice levels.
In general, IDM infants are more prone to hyperbilirubinemia even beyond the polycythemia. The causes are thought to be multifactorial. Macrosomic infants tend to have an increased amount of bruising at birth as well which leads to additional red blood cell breakdown and results in an increased volume of bilirubin in the liver. Additionally, as we mentioned, IDM infants are delivered early and preterm infants are also more prone to elevated bilirubin levels as are those infants that eat poorly which as I also said is a common characteristic of an IDM baby. The treatment for infants with elevated bilirubin is typically phototherapy with either a bilirubin blanket or overhead phototherapy and close monitoring of the bilirubin levels. The phototherapy helps to change the structure of the bilirubin so it can be more easily excreted in the urine and/or stool.
Electrolyte Disturbances
Hypocalcemia
The infant of the diabetic mother is also at risk for abnormal electrolyte levels, most commonly hypocalcemia or low calcium levels and hypomagnesemia or low magnesium levels. The infant’s hypocalcemia is directly related to the severity of the maternal diabetes. It is attributed to the infant’s poor response from the parathyroid gland to increase the parathyroid hormone in response to the low calcium levels. The normal parathyroid response that typically occurs on the 2nd or 3rd day after birth in most newborns does not occur until 48 hours or later in the IDM infant. Up to 50% of infants of diabetic mothers will experience low calcium levels. Close monitoring of electrolytes is key and symptomatic infants may require supplemental calcium through their IV.
Hypomagnesemia
Low magnesium levels have also been found in up to 33% of infants of diabetic mothers due to low maternal magnesium levels. And just as with low calcium levels in the IDM, the frequency and severity of low magnesium levels are directly correlated to how well controlled the blood sugars were during the pregnancy and if insulin was required. The magnesium levels will be monitored closely on the infant.
Hypoglycemia – pathophysiology
Now, obviously, the infant of the diabetic mother is at risk of hypoglycemia or low blood sugar levels, but I decided to discuss it last since it is the most common and I’ll go over a more detailed treatment plan.
Let’s start with a quick review of the pathophysiology behind hypoglycemia. In infants of diabetic mothers, the fetus in utero becomes hyperglycemic because of the increased transfer of glucose across the placenta due to the elevated glucose levels from the mother. With this rise of glucose levels in the fetus, the fetal pancreas increases the amount of insulin produced. Unfortunately after delivery, the infant’s source of glucose is abruptly removed, yet the levels of insulin remain elevated which leads to low blood sugars or hypoglycemia.
The incidence of hypoglycemia in IDM infants ranges from 15-75%. Infants of diabetic mothers typically experience the lowest levels of blood glucose 1-2 hours after birth and they generally increase to a more stable level by 12 hours of age. Infants who were exposed in utero to poorly controlled blood sugars are at an increased risk of developing hypoglycemia shortly after delivery.
What is the definition of neonatal hypoglycemia?
What is the definition of neonatal hypoglycemia? Unfortunately, despite many years of research, there is no consensus on the definition of neonatal hypoglycemia in healthy or high-risk newborns. Part of that is due to the fact that there has not been a specific glucose concentration defined or a specific duration of hypoglycemia that can predict neurological injury in infants. And to make it more difficult, there is not a single concentration or range of plasma glucose concentrations that are associated with clinical symptoms. Each infant and when they become symptomatic varies. According to the American Academy of Pediatrics, neonatal glucose concentrations below 45 mg/dL during the first 2 days of life are generally considered hypoglycemic. But even with that number in mind, the treatment varies based on the age of the infant, whether or not they are symptomatic, and between different institutions.
Hypoglycemia – Symptoms, Treatment and Plan of Care
Symptoms of hypoglycemia include jitteriness, a weak or high-pitched cry, poor tone, lethargy, poor feeding, apnea, seizures, tachypnea, and/or cyanosis.
Infants identified to be at risk for hypoglycemia will have their blood sugars monitored closely after birth. Those infants include infants of diabetic mothers, large for gestational age infants > 34 weeks, those that are small for gestational age, and late preterm infants delivered between 34 and 36 6/7 weeks. These infants known to be at risk should be fed every 2-3 hours and screened before feedings based on the institution’s policy. I always encourage the parents of infants who are at risk for hypoglycemia to eat early and often!
But if despite feeding the infant within the first hour of life and every 2-3 hours, the blood sugars remain low, additional interventions will need to be done. The point at which interventions are indicated will be tailored to each particular clinical situation and the characteristics of the infant. The treatment of hypoglycemia is a stepwise approach consistent with the American Academy of Pediatrics’ recommendations.
IV Dextrose
Since severe, prolonged, and symptomatic hypoglycemia can result in neurological injury, prompt and aggressive intervention is necessary with any symptomatic infant. With these infants, an IV will need to be started for a bolus of D10W at 2 ml/kg followed by a maintenance infusion at a glucose infusion rate of 5-8 mg/kg/min. Blood sugars will be monitored 30-60 minutes after the initiation of therapy and will be followed closely thereafter. The D10W rate will be adjusted or increased based on the blood sugars with an initial goal of > 50 mg/dL in the first 48 hours and > 60 mg/dL after 48 hours of age.
The percentage of glucose in the IV fluids may need to be increased to a D12.5 solution or possibly a D15 if the blood glucoses fail to normalize despite rate increases with the D10W. If a solution greater than D12.5 is required, it will need to be infused via a central line either a UVC or PICC line.
Once the infant’s glucose levels stabilize and are maintained at or above the desired value, the dextrose solution will be slowly tapered down. Some infants push back to the weaning of the dextrose solution and the weaning will have to be paused or the rate increased back up if the blood sugar decreases again. Typically infants can continue to be breastfed or given expressed breast milk or formula while on the IV dextrose solution. Based on the institutional policy, gavage or tube feeding may be considered if the infant is not breast or bottle feeding well.
For asymptomatic infants at risk, the initial focus is on breastfeeding or orally feeding the infant early and often. Again, every institution and their management will vary, but according to the American Academy of Pediatrics and World Health Organization, the infant should receive their initial feeding within the first hour of life followed by a blood sugar check 30 minutes post feeding. Treatment from there is based on each institution’s policy. The acceptable blood glucose range varies with less latitude once the infant is greater than 4 hours of age. If the infant ever becomes symptomatic, they should automatically receive IV dextrose.
Glucose Gel
A fairly new approach that has been successful with some hypoglycemic infants is the oral administration of dextrose or glucose gel. Buccal 40% dextrose gel is an effective and safe therapy when used in conjunction with milk feeding for asymptomatic hypoglycemic infants. Studies have shown that glucose gel can also be used in conjunction with breastfeeding and formula fed infants. The use of glucose gel with feedings has reduced the need for IV dextrose, minimized separation between the infant and mother and it promotes breastfeeding. The gel dose is based on the infant’s weight and administered in the infant’s cheeks. It is recommended that the glucose gel is only given 2-3 times max. Beyond that, if the infant continues to have persistent hypoglycemia, they should receive IV Dextrose.
The ultimate goal within the first 24 hours is to maintain the blood sugar > 45 mg/dL. If the infant’s blood sugar stabilizes at or above 45 mg/dL when checked prior to several feedings, many institution’s protocol is to discontinue checking them with the assumption that the infant remains asymptomatic. But again, the policy will vary between different institutions.
If an infant has persistent hypoglycemia and the providers are unable to wean the infant off of IV dextrose, further work-up will need to be done.
Follow-up Care for the IDM
The follow-up care for an IDM infant is dependent upon the specific complications and consultations for follow-ups should be made accordingly. Adverse long-term outcomes have been correlated with the severity and duration of severe hypoglycemia. These infants are at an increased risk for intellectual impairment, obesity, impaired glucose tolerance, and/or hypertension.
Closing
I know that may have been a large amount of information to take, in, but as you just read, the infant of the diabetic mother is at risk for several complications. Many parents may have been informed that their infant may have some low blood sugars, but unfortunately, they are not always informed of all of the other potential complications that are common to the IDM infant.
I hope this review has been helpful if you have either preexisting or gestational diabetes so you are more informed of what complications may occur with your infant. As always, ask your provider what the plan of care is for your particular infant. What I presented here are general guidelines, but each institution is likely to have a thorough policy in place to follow for infants of diabetic mothers.
As always, share our podcast or this particular episode with someone who you feel would benefit from it.
A big thank you to Laura and Marc Bialeschki and their beautiful daughter, Audrey for the inspiration of this episode and for allowing Audrey to model for our podcast cover!
Remember, once empowered with knowledge, you have the ability to change the course.
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