Amniotic fluid index
Amniotic fluid index (AFI) is a rough estimate of the amount of amniotic fluid[1] and is an index for the fetal well-being. It is a part of the biophysical profile.[1]
AFI is the score (expressed in cm) given to the amount of amniotic fluid seen on pregnant uterus and calculated by a ultrasonograph (aka ultrasound). 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 8-18 is considered normal[5]. Median AFI level is approximately 14 from week 20 to week 35[6], when the amniotic fluid begins to reduce in preparation for birth.
- An AFI < 5-6 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]
References
- ^ a b Tom C Winter; Sanders, Roger C. (2006). Clinical Sonography: A Practical Guide. Hagerstown, MD: Lippincott Williams & Wilkins. pp. p502. ISBN 0-7817-4869-0. http://books.google.com/books?id=KUd6bLOtrxoC&pg=PA502&dq=%22Amniotic+Fluid+Index%22&lr=&as_brr=3&ei=D5hzSL-OHJPgiQGZodHpBw&sig=ACfU3U1KFI2U2NCQmg31qs_QnlaBm6Dw3Q.
- ^ http://www.perinatology.com/Reference/glossary/A/Amniotic%20Fluid%20Index.htm
- ^ 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. pp. p105. ISBN 1-4051-0380-9. http://books.google.com/books?id=YsHwGCYi0YAC&pg=PA105&dq=%22Amniotic+Fluid+Index%22+Oligohydramnios&lr=&as_brr=3&ei=fZlzSMzkA5ykjgHJ1cDpBw&sig=ACfU3U1EbKtOGTTXoR5CcrzbiVepm-BrDg.
- ^ http://www.americanpregnancy.org/pregnancycomplications/lowamnioticfluidoligohydramnios.htm
- ^ http://www.gynob.com/biopamfl.htm
- ^ http://www.fetalanomalies.org/Fluid.html
- ^ 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. http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=000265554.
- ^ Sylvia Dobo; Mitchell King; Lipsky, Martin S.; Jeff Susman (2003). Family Medicine Certification Review. Cambridge, MA: Blackwell Publishers. pp. p133. ISBN 1-4051-0329-9. http://books.google.com/books?id=ETS89YmvaIkC&pg=PT144&dq=%22Amniotic+Fluid+Index%22+Polyhydramnios&lr=&as_brr=3&ei=UppzSKvyGYHsiQGM-oGiCQ&sig=ACfU3U2vkbEgR2-mupYggbnhsdYJ2C67ig#PPT144,M1.