Intrauterine growth restriction

Last updated: September 20, 2021

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Intrauterine growth restriction (IUGR) is defined as lower than normal fetal growth characterized by an estimated fetal weight below the 10th percentile for a given gestational age. There are two types of IUGR: asymmetrical and symmetrical. Asymmetrical IUGR is caused by extrinsic influences (most commonly placental insufficiency) that affect the fetus in the later stages of gestation and symmetrical IUGR is caused by intrinsic influences (e.g., early intrauterine infections, aneuploidy) that affect the fetus in the early stages of gestation. IUGR is diagnosed with serial ultrasound, which demonstrates decreased fetal growth and oligohydramnios. Typical manifestations of asymmetrical IUGR are a normal fetal head size with a disproportionately small body and limbs, while symmetrical IUGR typically manifests with a global growth restriction of the head and body and can lead to an increased risk of neurologic sequelae. Treatment should address the underlying cause. Regular nonstress test (NST), contraction stress test (CST), and biophysical profile (BPP) are recommended to closely monitor fetal status and placental development. Labor induction or cesarean delivery should be considered if the infant is close to term or if there are signs of nonreassuring fetal status.

Epidemiological data refers to the US, unless otherwise specified.

Maternal causes

Uteroplacental causes

Fetal factors

Asymmetrical IUGR is the most common manifestation of IUGR (∼ 70%), has a late onset, and is usually due to maternal systemic disease (e.g., hypertension) that results in placental insufficiency. Symmetrical IUGR is less common (∼ 30%) and is usually due to a genetic disorder (e.g., aneuploidy), congenital heart disease, or early intrauterine TORCH infection that affects the fetus early in gestation.


Asymmetrical IUGR

Caused by extrinsic factors, which affect the fetus in the later stages of gestation (i.e., third trimester).

Symmetrical IUGR

Caused by intrinsic factors (e.g., genetic abnormalities, infections), which affect the fetus in the early stages of gestation.


Fetal signs

  • Small for gestational age (or with a birth weight below 10th percentile) [3]
  • Decreased or absent fetal movements [7]
  • Asymmetrical IUGR: disproportionate growth restriction
    • The dimensions of the head are normal while the body and limbs are thin and small.
  • Symmetrical IUGR: global growth restriction
    • The entire body is proportionally small.
    • The circumference of the head is proportional to the rest of the fetal body.
    • ↑ Risk of neurologic sequelae [8]

Maternal signs

We list the most important complications. The selection is not exhaustive.

  1. Placental Calcification. Updated: January 1, 2017. Accessed: October 27, 2017.
  2. Biophysical Profile Score (BPS or BPP). Updated: January 1, 2016. Accessed: October 27, 2017.
  3. Beckmann CRB. Obstetrics and Gynecology. Lippincott Williams & Wilkins ; 2010
  4. Swanson RW, Tallia AF, Scherger JE, Dickey N. Swanson's Family Medicine Review. Elsevier Health Sciences ; 2009
  5. Kenneth Leveno, Steven Bloom, Brian Casey, Jodi Dashe, Barbara Hoffman, Catherine Spong, F. Gary Cunningham. Williams Obstetrics. McGraw-Hill Education Ltd ; 2018
  6. Resnik R. Fetal Growth Restriction: Evaluation and Management. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. updated: October 12, 2017. Accessed: April 27, 2017.
  7. Sharma D, Shastri S, Sharma P. Intrauterine Growth Restriction: Antenatal and Postnatal Aspects. Clin Med Insights Pediatr. 2016; 10 : p.67–83. doi: 10.4137/cmped.s40070 . | Open in Read by QxMD
  8. Ross M.G.. Fetal growth restriction. In: Smith C.V., Fetal growth restriction. New York, NY: WebMD. Updated: July 25, 2018. Accessed: May 2, 2019.
  9. Baschat DAA. Fetal responses to placental insufficiency: an update. BJOG. 2004; 111 (10): p.1031-1041. doi: 10.1111/j.1471-0528.2004.00273.x . | Open in Read by QxMD
  10. Intrauterine Growth Retardation. . Accessed: April 1, 2019.
  11. Belizán JM, Villar J, Nardin JC, Malamud J, De Vicurna LS. Diagnosis of intrauterine growth retardation by a simple clinical method: measurement of uterine height.. Am J Obstet Gynecol. 1978; 131 (6): p.643-6. doi: 10.1016/0002-9378(78)90824-4 . | Open in Read by QxMD
  12. Foley MR, Lockwood CJ, Gersh BJ, Eckler K. Maternal Cardiovascular and Hemodynamic Adaptations to Pregnancy. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. updated: November 11, 2015. Accessed: April 27, 2017.
  13. Placental insufficiency. Updated: April 10, 2016. Accessed: April 27, 2017.
  14. Dutta DC, Konar H. Textbook of Obstetrics. Jaypee Brothers Medical Publishers ; 2015
  15. Jacob A. A Comprehensive Textbook of Midwifery and Gynecological Nursing, Third Edition. JP Medical Ltd ; 2012
  16. Oligohydramnios. Updated: January 1, 2014. Accessed: October 27, 2017.

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