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Fetal Macrosomia

Medically reviewed by Last updated on Dec 2, 2022.

What is fetal macrosomia (FM)?

FM generally means that your baby weighs more than 8.82 pounds (4,000 grams) at birth. You may hear a similar term, large for gestational age, which means your baby weighs more than other babies at the same gestational age.

What increases my baby's risk for FM?

  • Being born past 40 weeks gestation
  • A mother with diabetes
  • A mother or sibling who was born with FM
  • A mother who is obese or gains a lot of weight during pregnancy
  • Being male

How is FM diagnosed and managed?

Your baby's healthcare provider may predict FM before birth, but it is usually diagnosed after your baby is born. The provider may recommend a C-section to deliver your baby. This may decrease your and your baby's risk for complications during delivery.

What are the risks of FM for me?

You may bleed more than expected during delivery. Your pelvic organs may be damaged. These problems may become life-threatening.

What are the risks of FM for my baby?

Your baby may have low blood sugar levels after birth. Your baby's bones or nerves may be damaged before or during birth. He or she may not get enough oxygen before or during birth. Your baby may need to stay in a neonatal intensive care unit (NICU) to monitor or treat these problems. It is rare that your baby will have long term problems.

How can I help prevent FM?

  • Stay active. Activity will help you maintain or reach a healthy weight. Do 30 minutes of activity most days of the week. Talk to your healthcare provider about the type of activity that is best for you.
  • Eat plenty of healthy foods. Healthy foods will help you maintain or reach a healthy weight. Healthy foods include fruits, vegetables, whole-grain breads, low-fat dairy products, beans, lean meats, and fish.
  • Manage your diabetes during pregnancy. Follow your eating and exercise plan. Take your diabetes medicine as directed. Check your blood sugar levels 3 times each day or as directed.

When should I call my baby's doctor?

  • You have questions or concerns about your baby's condition or care.

Care Agreement

You have the right to help plan your baby's care. Learn about your baby's health condition and how it may be treated. Discuss treatment options with your baby's healthcare providers to decide what care you want for your baby. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.