Sometimes a baby developing in the womb grows to be much larger than normal. The medical term for this is fetal macrosomia. It is not always clear what causes fetal macrosomia, but if you are over the age of 35, obese, overdue for your delivery or have diabetes, you are at greater risk. Sometimes the cause of fetal macrosomia is genetic.

Fetal macrosomia can put both you and your baby at risk for birth injuries during or after delivery. Here are some of the possible complications of fetal macrosomia.

Risks to the child

A baby with fetal macrosomia may have hypoglycemia at birth. In other words, the baby’s blood sugar level may be too low. Symptoms of hypoglycemia in a newborn include:

  • Hypothermia
  • Respiratory distress
  • Abnormal heart rate
  • Seizure
  • Lethargy or coma

Not all hypoglycemic babies show symptoms.

Complications of fetal macrosomia can continue into childhood. Your baby may be at greater risk for eventually developing metabolic syndrome, a cluster of conditions that occur together and increase the child’s risk for diabetes, stroke or heart disease. Symptoms of metabolic syndrome include abnormal cholesterol levels, excess body fat, increased blood sugar and blood pressure. An abnormally high weight at birth can also put your child at risk for childhood obesity.

Risks to the mother

If your baby has fetal macrosomia, it may be too large for the birth canal to accommodate it. This can cause tearing of the tissues of your vagina and of the muscles of your pelvic floor. Fetal macrosomia can complicate labor and delivery to the point where you have to have an emergency cesarean section or an operative vaginal delivery using a vacuum device or forceps. If you already have a history of uterine surgery, fetal macrosomia can cause a rupture of the uterus at the site of the previous incision. Fetal macrosomia can also lead to serious postpartum bleeding.

Another possible complication of fetal macrosomia is shoulder dystocia. This occurs when the baby’s shoulder becomes wedged under your pelvis. Shoulder dystocia poses a risk of injury to both you and your baby.