Fetal macrosomia poses health risks for you and your baby — both during pregnancy and after childbirth.

Maternal risks

Possible maternal complications of fetal macrosomia might include:

  • Labor problems. Fetal macrosomia can cause a baby to become wedged in the birth canal, sustain birth injuries, or require the use of forceps or a vacuum device during delivery (operative vaginal delivery). Sometimes a C-section is needed.
  • Genital tract lacerations. During childbirth, fetal macrosomia can cause a baby to injure the birth canal — such as by tearing vaginal tissues and the muscles between the vagina and the anus (perineal muscles).
  • Bleeding after delivery. Fetal macrosomia increases the risk that your uterine muscles won't properly contract after you give birth (uterine atony). This can lead to potentially serious bleeding after delivery.
  • Uterine rupture. If you've had a prior C-section or major uterine surgery, fetal macrosomia increases the risk of uterine rupture — a rare but serious complication in which the uterus tears open along the scar line from the C-section or other uterine surgery. An emergency C-section is needed to prevent life-threatening complications.

Newborn and childhood risks

Possible complications of fetal macrosomia for your baby might include:

  • Lower than normal blood sugar level. A baby diagnosed with fetal macrosomia is more likely to be born with a blood sugar level that's lower than normal.
  • Childhood obesity. Research suggests that the risk of childhood obesity increases as birth weight increases.
  • Metabolic syndrome. If your baby is diagnosed with fetal macrosomia, he or she is at risk of developing metabolic syndrome during childhood.

    Metabolic syndrome is a cluster of conditions — increased blood pressure, a high blood sugar level, excess body fat around the waist or abnormal cholesterol levels — that occur together, increasing the risk of heart disease, stroke and diabetes.

Further research is needed to determine whether these effects might increase the risk of adult diabetes, obesity and heart disease.

April 16, 2015