(Large for Gestational Age; LGA)

How to Say It: mak-row-SOHM-ee-uh


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

Copyright © Nucleus Medical Media, Inc.


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

Centers for Disease Control and Prevention


Women's Health Matters

Society of Obstetricians and Gynaecologists of Canada


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: Updated July 13, 2018. Accessed August 7, 2018.

6/16/2015: DynaMed Systematic Literature Surveillance 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.

Last reviewed September 2020 by EBSCO Medical Review Board Elliot M. Levine, MD, FACOG