Amniotic fluid index

Amniotic fluid index
Purposeestimate of amniotic fluid and an indicator of fetal well-being

Amniotic fluid index (AFI) is a quantitative estimate of amniotic fluid[1] and an indicator of fetal well-being. It is a separate measurement from the biophysical profile.[1]

AFI is the score (expressed in centimetres) given to the amount of amniotic fluid seen on ultrasonography of a pregnant uterus. To determine the AFI, doctors may use a four-quadrant technique,[2] when the deepest, unobstructed, vertical length of each pocket of fluid is measured in each quadrant and then added up to the others,[3] or the so-called "single deepest pocket" technique.[4]

An AFI between 8 and 18 cm is considered normal.[5] Median AFI level is approximately 14 cm from week 20 to week 35,[6] when the amniotic fluid begins to reduce in preparation for birth. An AFI smaller than 5–6 cm is considered as oligohydramnios.[3] The exact number can vary by gestational age. The fifth percentile for gestational age is sometimes used as a cutoff value.[7] An AFI larger than 24–25 cm is considered as polyhydramnios.[3][8]

  1. ^ a b Tom C Winter; Sanders, Roger C. (2006). Clinical Sonography: A Practical Guide. Hagerstown, MD: Lippincott Williams & Wilkins. p. 502. ISBN 0-7817-4869-0.
  2. ^ "perinatology.com Glossary". www.perinatology.com.
  3. ^ a b c Carr, Phyllis L.; Ricciotti, Hope; Freund, Karen M.; Scott Kahan (2003). In a Page Ob/Gyn & Women's Health (In a Page). Cambridge, MA: Blackwell Publishers. p. 105. ISBN 1-4051-0380-9.
  4. ^ "Los Bajos Niveles de Líquido Amniótico: Oligohidramnios". 2012-04-27.
  5. ^ "PRO: Amniotic Fluid - Biophysical Profile - the virtual ObGyn office".
  6. ^ "Amniotic Fluid Index". Archived from the original on 2019-02-04.
  7. ^ Griffin M, Attilakos G, Greenwood R, Denbow M (2009). "Amniotic fluid index in low-risk, post-dates pregnancies". Fetal Diagn. Ther. 26 (4): 212–5. doi:10.1159/000265554. PMID 20029220. S2CID 33665604.
  8. ^ Sylvia Dobo; Mitchell King; Lipsky, Martin S.; Jeff Susman (2003). Family Medicine Certification Review. Cambridge, MA: Blackwell Publishers. p. 133. ISBN 1-4051-0329-9.