Many factors might increase the risk of fetal macrosomia — some modifiable, some not.
- Maternal diabetes. If you had diabetes before pregnancy (pre-gestational diabetes) or develop diabetes during pregnancy (gestational diabetes), fetal macrosomia is more likely. If your diabetes is poorly controlled, your baby is likely to have larger shoulders and greater amounts of body fat than would a baby whose mother doesn't have diabetes.
- A history of fetal macrosomia. If you've previously given birth to a baby diagnosed with fetal macrosomia, you're at increased risk of having another baby who has the condition. Also, if you weighed more than 8 pounds, 13 ounces at birth, you're more likely to have a large baby.
- Maternal obesity. Fetal macrosomia is more likely if you're obese.
- Excessive weight gain during pregnancy. Gaining too much weight during pregnancy increases the risk of fetal macrosomia.
- Previous pregnancies. The risk of fetal macrosomia increases with each pregnancy. Up to the fifth pregnancy, the average birth weight for each successive pregnancy typically increases by up to about 4 ounces (120 grams).
- You're having a boy. Male infants typically weigh slightly more than female infants. Most babies who weigh more than 9 pounds, 15 ounces (4,500 grams) are male.
- Overdue pregnancy. If your pregnancy continues by more than two weeks past your due date, your baby is at increased risk of fetal macrosomia.
- Maternal age. Women older than 35 are more likely to have a baby diagnosed with fetal macrosomia.
Fetal macrosomia is more likely to be a result of maternal diabetes, obesity or weight gain during pregnancy than other causes. If these risk factors aren't present and fetal macrosomia is suspected, it's possible that your baby might have a rare medical condition that affects fetal growth. Your health care provider might recommend prenatal diagnostic tests and perhaps a visit with a genetic counselor, depending on the test results.
May. 24, 2012
- American College of Obstetricians and Gynecologists. Your Pregnancy and Childbirth Month to Month. 5th ed. Washington, D.C.: American College of Obstetricians and Gynecologists; 2010:241.
- Abramocwicz JS, et al. Fetal macrosomia. http://www.uptodate.com/index. Accessed March 13, 2012.
- Rodis JF. Timing and route of delivery in pregnancies at risk of shoulder dystocia. http://www.uptodate.com/index. Accessed March 13, 2012.
- Mandy GT. Large for gestational age newborn. http://www.uptodate.com/index. Accessed March 13, 2012.
- Cunningham FG, et al. Williams Obstetrics. 23rd ed. New York, N.Y.: The McGraw-Hill Companies; 2010. http://www.accessmedicine.com/content.aspx?aID=6036563. Accessed March 14, 2012.
- DeCherney AH, et al.. Current Diagnosis & Treatment Obstetrics & Gynecology. 10th ed. New York, N.Y.: The McGraw-Hill Companies; 2007. http://www.accessmedicine.com/content.aspx?aID=2384988. Accessed March 14, 2012.
- Gibbs RS, et al. Danforth's Obstetrics and Gynecology. 10th ed. Philadelphia, Pa.: Wolters Kluwer Health Lippincott Williams & Wilkins; 2008. http://www.danforthsobgyn.com. Accessed March 19, 2012.
- Chatfield J. ACOG issues guidelines on fetal macrosomia. American Family Physician. 2001;64:169.
- Rodis JF. Intrapartum management and outcome of shoulder dystocia. http://www.uptodate.com/index. Accessed March 20, 2012.
- Routine prenatal care. Bloomington, Minn.: Institute for Clinical Systems Improvement. http://www.icsi.org/guidelines_and_more/gl_os_prot/womens_health/prenatal_care_4/prenatal_care__routine__3.html. Accessed March 20, 2012.
- Tse G, et al. Weight gain and loss in pregnancy. http://www.uptodate.com/index. Accessed March 20, 2012.
- Mulik, et al. The outcome of macrosomic fetuses in a low risk primigravid population. International Journal of Gynecology and Obstetrics. 2003;80:15.
- Hackmon R, et al. Combined analysis with amniotic fluid index and estimated fetal weight for prediction of severe macrosomia at birth. American Journal of Obstetrics and Gynecology. 2007;196:333.e1.
- American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins - Obstetrics. ACOG Practice Bulletin No.60. Pregestational diabetes mellitus. Obstetrics & Gynecology. 2005;105:675.
- Raio L, et al. Perinatal outcome of fetuses with a birth weight greater than 4500 g: An analysis of 3356 cases. European Journal of Obstetrics and Gynecology and Reproductive Biology. 2003;109:160.
- Special tests for monitoring fetal health. American Congress of Obstetricians and Gynecologists. http://www.acog.org/publications/patient_education/bp098.cfm. Accessed March 20, 2012.
- Gillen-Goldstein J, et al. Assessment of fetal lung maturity. http://www.uptodate.com/index. Accessed March 20, 2012.
- Wegner EK, et al. Operative vaginal delivery. http://www.uptodate.com/index. Accessed March 21, 2012.
- McCulloch DK, et al. Prediction and prevention of type 2 diabetes. http://www.uptodate.com/index. Accessed March 21, 2012.
- What is metabolic syndrome? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/ms/. Accessed March 21, 2012.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. March 22, 2012.
- Cleary-Goldman J, et al. Impact of maternal age on obstetric outcome. Obstetrics & Gynecology. 2005;105:983.
You Are ... The Campaign for Mayo Clinic
Mayo Clinic is a not-for-profit organization. Make a difference today.