Definition

A fetus (baby) of a mother with diabetes may be exposed to high blood sugar (glucose) levels throughout the pregnancy.

Alternative Names

IDM; Gestational diabetes - IDM; Neonatal care - diabetic mother

Causes

There are two forms of diabetes during pregnancy:

• Gestational diabetes -- high blood sugar (diabetes) that starts or is first detected during pregnancy
• Pre-existing or pre-gestational diabetes -- already having diabetes before becoming pregnant

If diabetes is not well controlled during pregnancy, the baby is exposed to high blood sugar levels. This can affect the baby and mother during pregnancy, at the time of birth, and after birth.

Infants of diabetic mothers (IDM) are often larger than other babies, especially if diabetes is not well-controlled. This may make vaginal birth harder and may increase the risk for nerve injuries and other trauma during birth. Also, cesarean births are more likely.

An IDM is more likely to have periods of low blood sugar (hypoglycemia) shortly after birth, and during the first few days of life. This is because the baby has been used to getting more sugar than needed from the mother. They have a higher insulin level than needed after birth. Insulin lowers the blood sugar. It can take days for babies' insulin levels to adjust after birth.

IDMs are more likely to have:

• Breathing difficulty due to less mature lungs
• High red blood cell count (polycythemia)
• High bilirubin level (newborn jaundice)
• Thickening of the heart muscle between the large chambers (ventricles)

If diabetes is not well-controlled, chances of miscarriage or stillbirth are higher.

An IDM has a higher risk of birth defects if the mother has pre-existing diabetes that is not well controlled from the very beginning.

Symptoms

The infant is often larger than usual for babies born after the same length of time in the mother's womb (large for gestational age). In some cases, especially if mothers have more longstanding illness, the baby may be smaller (small for gestational age).

Other symptoms may include:

• Blue skin color, rapid heart rate, rapid breathing (signs of immature lungs or heart failure)
• Poor sucking, lethargy, weak cry
• Seizures (sign of severe low blood sugar)
• Poor feeding
• Puffy face
• Tremors or shaking shortly after birth
• Jaundice (yellow skin color)

Exams and Tests

Before the baby is born:

• Ultrasound in the last few months of pregnancy can monitor the size of the baby.
• Lung maturity testing may be done on the amniotic fluid. This is VERY rarely done but may be helpful if the due date was not determined early in the pregnancy. Delivery before 39 weeks is not generally recommended for IDMs.

After the baby is born:

• The baby's blood sugar will be checked within the first hour or two after birth, and rechecked regularly until it is consistently normal. This may take a day or two, or even longer.
• The baby will be watched for signs of trouble with the heart or lungs.
• The baby's bilirubin will be checked before going home from the hospital, and sooner if there are signs of jaundice.
• An echocardiogram may be done to look at the size of the baby's heart.

Treatment

All infants who are born to mothers with diabetes should be tested for low blood sugar, even if they have no symptoms.

Efforts are made to ensure the baby has enough glucose in the blood:

• Feeding soon after birth may prevent low blood sugar in mild cases. Even if the plan is to breastfeed, the baby may need some donor milk or formula supplementation during the first 8 to 24 hours if the blood sugar is low and there is no maternal breast milk available.
• Many hospitals are now giving dextrose (glucose) gel inside the baby's cheek in addition to supplementation.
• Low blood sugar that does not improve with feeding is treated with fluid containing sugar (glucose) and water given through a vein (IV).
• In severe cases, if the baby needs large amounts of sugar, fluid containing higher concentrations of glucose must be given through an umbilical (belly button) vein for several days.

Rarely, the infant may need breathing support or medicines to treat other effects of diabetes. High bilirubin levels are treated with light therapy (phototherapy).

Outlook (Prognosis)

In most cases, an infant's symptoms go away within hours, days, or a few weeks. However, an enlarged heart may take several months to get better.

Very rarely, blood sugar may be so low as to cause brain damage.

Possible Complications

The risk of stillbirth is higher in women with diabetes that is not well controlled. There is also an increased risk for a number of birth defects or problems:

• Congenital heart defects.
• High bilirubin level (hyperbilirubinemia).
• Immature lungs.
• Neonatal polycythemia (more red blood cells than normal). This may cause a blockage in the blood vessels or hyperbilirubinemia.
• Small left colon syndrome. This causes symptoms of intestinal blockage.
• Difficulty with delivery due to large size of the baby (if blood sugar is not well controlled).

When to Contact a Medical Professional

If you are pregnant and getting regular prenatal care, routine testing will show if you develop gestational diabetes.

If you are pregnant or planning pregnancy and have diabetes that is not under control, contact your health care provider right away.

If you are pregnant and are not receiving prenatal care, contact a provider for an appointment.

Prevention

Women with diabetes need special care during pregnancy to prevent problems. Controlling blood sugar can prevent many problems.

Carefully monitoring the infant in the first hours and days after birth may prevent health problems due to low blood sugar.

References

Garg M, Devaskar SU. Disorders of carbohydrate metabolism in the neonate. In: Martin RJ, Fanaroff AA, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant. 12th ed. Philadelphia, PA: Elsevier; 2025:chap 90.

Landon MB, Catalano PM, Gabbe SG. Diabetes mellitus complicating pregnancy. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 45.

Moore TR, Hauguel-De Mouzon S, Catalano P. Diabetes in pregnancy. In: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 59.

Paauw ND, Stegeman R, de Vroede MAMJ, Termote JUM, Freund MW, Breur JMPJ. Neonatal cardiac hypertrophy: the role of hyperinsulinism-a review of literature. Eur J Pediatr. 2020;179(1):39-50. PMID: 31840185 pubmed.ncbi.nlm.nih.gov/31840185/.

Sheanon NM, Muglia LJ. The endocrine system. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 127.