Definition

A baby who is small for gestational age (SGA) has a significantly lower weight than other babies of the same gestational age. Gestational age is the number of weeks into pregnancy.

Causes

If parents have small stature, the baby may be small. These babies have normal development but are just small compared to others their age.

SGA sometimes occurs if there are growth and development problems before birth. These may occur with:

• Problems with the supply of nutrients and oxygen to the baby or a small uterus—can cause a condition known as intrauterine growth restriction (IUGR)
• Exposure to toxic substances or certain medications
• Infections or chronic illness during pregnancy
• Birth defects
• Genetic syndromes

Risk Factors

Parents with small stature increase the risk of SGA.

Maternal factors that can affect a baby’s growth during pregnancy include:

• High blood pressure
• Smoking
• Substance abuse
• Excessive use of alcohol
• Not taking folic acid supplements during pregnancy
• A prior birth of a SGA baby
• Chronic medical conditions, such as kidney failure, diabetes, asthma, lupus, or anemia
• Previous bariatric surgery
• Certain medications
• Certain infections
• Malnutrition
• Silver-Russell syndrome

Other factors that can affect baby’s growth include:

• Pregnancy with more than 1 child
• Birth defects
• Genetic syndromes in the baby
• Problems with the placenta, such as placental abruption or placenta previa

Symptoms

Symptoms of SGA include a birth weight that is in the lowest 10% of babies with same gestational age.

Diagnosis

A physical exam will be done. A baby with SGA is often diagnosed before birth based on measurements taken of the mother’s abdomen, the mother’s weight, and size of the uterus (womb). If the measurement is low for the number of weeks of pregnancy, then the baby may be smaller than average. SGA may also be diagnosed at birth based on the baby’s weight and height.

Images may be taken during pregnancy with an ultrasound.

Treatment

Talk with your doctor about the best treatment plan for your baby. A baby with SGA is at higher risk for problems, such as difficulty feeding, blood sugar abnormalities, and breathing problems. Your baby’s health and development will be monitored closely.

Babies that have SGA due to lack of nutrition or oxygen may need treatment. Options include:

Prevention

SGA due to family traits cannot be prevented.

If you are thinking of becoming pregnant, taking a supplement containing folic acid may reduce the risk of having a small for gestational age baby.

To help reduce your baby’s chance of getting SGA due to nutrition and oxygen problems during birth, take these steps during pregnancy:

• If you smoke, talk to your doctor about ways to quit.
• If you use drugs or alcohol, ask your doctor to refer you to a treatment program that will help you stop.
• Start prenatal care early and continue throughout pregnancy.
• Keep any chronic condition under good control.

Healthy Children—American Academy of Pediatrics http://www.healthychildren.org

Health Canada http://www.hc-sc.gc.ca

Intrauterine growth restriction (IUGR); Small for gestational age (SGA). American Pregnancy Association website. Available at:
http://americanpregnancy.org/pregnancycomplications/iugr.htm
Updated January 2014. Accessed October 30, 2014.

Small for gestational age. Lucile Packard Children’s Hospital website. Available at:
http://www.lpch.org/DiseaseHealthInfo/HealthLibrary/hrnewborn/sga.html
Accessed October 30, 2014.

Small for gestational age babies. Patient UK website. Available at:
http://www.patient.co.uk/doctor/small-for-gestational-age-babies
Updated May 28, 2013. Accessed October 30, 2014.

Small for gestational age introduction. The MAGIC Foundation website. Available at:
http://www.magicfoundation.org/www/docs/111
Accessed October 30, 2014.

11/19/2013 DynaMed’s Systematic Literature Surveillance.
http://www.ebscohost.com/dynamed:
Roos N, Neovius M, et al. Perinatal outcomes after bariatric surgery: nationwide population based matched cohort study. BMJ 2013;347:f6460.

3/17/2015 DynaMed’s Systematic Literature Surveillance.
http://www.ebscohost.com/dynamed:
Hodgetts V, Morris R, et al. Effectiveness of folic acid supplementation in pregnancy on reducing the risk of small-for-gestational age neonates: a population study, systematic review and meta-analysis. BJOG. 2015 Mar;122(4):478-490.