Overview
Large babies are more common with diabetes, high weight gain, and past large babies.
Shoulder dystocia, where the shoulder gets stuck during birth, is a risk.
Most large babies are born healthy.
Doctors estimate size with ultrasound, but estimates can be off by a pound or more.
Symptoms
Common signs:
- Baby measuring large
Less common
- Long labor
When to get medical care
Call 911Heavy bleeding, severe belly pain, a seizure, or fluid that's green or brown with fewer baby movements: call 911 or go to labor and delivery.
Get care todayLabor not progressing.
See a doctor soonLarge baby concerns.
Causes
Diabetes, genes.
Does it spread or run in families?
- It isn't contagious. You can't catch it from someone else.
Who is more likely to get it
- Gestational diabetes
Possible complications
Diagnosis
Ultrasound estimates weight.
Treatment
Plan birth.
Self-care
- Control blood sugar in pregnancy
- Follow weight gain advice
Prevention
To lower your risk or prevent problems:
- Gestational diabetes screening
Which doctor treats this
- Start with your child's pediatrician.
Children, pregnancy, and older adults
- After birth: Baby's blood sugar may be checked.
For caregivers
- Learn the warning signs and when to call the doctor or 911.
- Keep a list of your child's medicines, doses, and doctors on your phone.
- Tell teachers, coaches, and sitters what to watch for and what to do.
- Take breaks and ask for help. Caregivers need care too.
Outlook
Most do well.
Most large babies do well.
Getting ready for your visit
Bring a list of your symptoms and medicines.
Questions to ask
- Should I plan a C-section?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Search ClinicalTrials.gov for studies on Large baby (macrosomia)
Sources
Last updated 2026-11-12.