Both the pregnant mother and baby face more risk if the baby is large for gestational age (macrosomia).
During pregnancy, it’s standard for a doctor or midwife to measure the height of the mother’s uterus. This measurement, combined with the number of weeks of pregnancy (gestational age), gives a sense of how large the baby is. A pregnant woman might feel a surge of pride if her doctor says her baby seems big for its age. Big means healthy, right?
Not always. Being too big can be a problem. A doctor may call this “large for gestational age,” or macrosomia. When a baby is too large, both the mother and baby are at greater risk during delivery. The baby may also be at greater risk for problems after birth. Know there are actions you can take to help reduce the risks for both you and your baby.
How large is too large?
A baby may be considered large for gestational age if he or she:
- Is estimated to be larger than 9 out of 10 babies of the same gestational age
- Weighs more than 4,000 grams (8 lbs 13 oz.) at birth
What factors increase the chance of having a large baby?
A woman is more likely to have a baby who is large for gestational age if she:
- Has diabetes (this is the most common cause)
- Has had other large babies
- Is large or obese
- Gained a lot of weight during pregnancy
What are the risks from a large baby?
A mother whose baby is too large has an increased risk of:
- A long and difficult birth
- An injury during delivery
- Having a C-section
A baby who’s too large has an increased risk of:
- Shoulder dystocia (shoulders getting stuck in the birth canal)
- Injury during delivery, such as a broken collarbone
- Low blood sugar after birth (if size is due to mother’s diabetes)
- Birth defects
- Breathing problems
What can be done to reduce the risks?
The doctor may want to do an ultrasound to get a better idea of the baby’s size before birth. If ultrasound shows that the baby is very large, a doctor might suggest inducing labor early so the baby is born before it gets bigger, or having a planned C-section. Both of these procedures have risks of their own. Be sure to discuss them with your doctor.
If you have diabetes, the most important thing you can do for your baby is to keep your blood sugar under control throughout pregnancy. This can reduce the risks for the baby both before and after birth.
Gaining the recommended amount of weight during pregnancy can also reduce your risk of having a large baby. Follow these weight gain guidelines if you’re pregnant with one baby. If you’re expecting multiples, ask your doctor how much weight you should gain:
|BMI before pregnancy:||Recommended weight gain during pregnancy:|
|Less than 18.5 (underweight)||28-40 lbs|
|18.5-24.9 (normal weight)||25-35 lbs|
|25-29.9 (overweight)||15-25 lbs|
|30 or more (obese)||11-20 lbs|