(Large for Gestational Age; LGA)


Macrosomia is when a baby is larger than normal before birth. Most babies are about 7 pounds (3.17 kilograms). Babies with this health problem are 8 pounds, 13 ounces (3.99 kilograms) or more.


The most common cause is diabetes in the mother during pregnancy.

Risk Factors

Things that may raise the risk are:

  • Mother having diabetes or gestational diabetes
  • Mother is obese
  • Mother and/or father of large size
  • Too much weight gain by the mother during pregnancy


The main sign is a predicted birth weight of at least 8 pounds, 13 ounces or more.


The doctor will ask about your symptoms and health history. A physical and pelvic exam will be done.

Pictures may be taken to estimate the birth weight. This can be done with ultrasound.

Ultrasound of Fetus
Fetal Ultrasound
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The goal of treatment is to safely deliver the baby. The baby may be too large to be delivered through the birth canal. A Cesarean delivery (C-section) may be done.


To lower the risk of this problem:

  • Get early prenatal care.
  • Maintain a healthy weight during pregnancy.
  • Manage diabetes.


American Congress of Obstetricians and Gynecologists  http://www.acog.org 

Centers for Disease Control and Prevention  http://www.cdc.gov 


Women's Health Matters  https://www.womenshealthmatters.ca 

Society of Obstetricians and Gynaecologists of Canada  http://sogc.org 


American College of Obstetricians and Gynecologists Committee on Practice Bulletins—Obstetrics. Practice Bulletin No. 190: Gestational Diabetes Mellitus. Obstet Gynecol. 2018 Feb;131(2):e49-e64, reaffirmed 2019.

Gestational diabetes mellitus (GDM). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/gestational-diabetes-mellitus-gdm. Updated July 13, 2018. Accessed August 7, 2018.

6/16/2015: DynaMed Systematic Literature Surveillance https://www.dynamed.com/condition/gestational-diabetes-mellitus-gdm: Wiebe HW, Boulé NG, et al. The effect of supervised prenatal exercise on fetal growth: a meta-analysis. Obstet Gynecol. 2015 May;125(5):1185-1194.

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