Amniotic fluid index
The amniotic fluid index (English Amniotic fluid index or AFI ) refers to a semi-quantitative ultrasound measurement method for determination of amniotic fluid volume . For the measurement, the pregnant woman's belly is divided into four quadrants and the largest amniotic fluid reservoir is measured vertically in each quadrant. The four values (in cm) are then added up. The classification of whether it is polyhydramnios or oligohydramnios depends on the week of pregnancy . The 5th and 95th percentiles of the AFI table are decisive for the diagnosis of oligo- or polyhydramnios. After the due date, for example, an AFI below 7 cm indicates insufficient amniotic fluid.
An alternative method of determining the amount of amniotic fluid is the vertical measurement of the largest depot (SDP - single deepest pocket), with values of 2 and 8 cm respectively being considered as the lower and upper norm limits. According to a Cochrane Review, determining the AFI compared to the SDP tends to overdiagnose oligohydramnios , which leads to more frequent medical intervention with no significant clinical benefit. Other sources consider the AFI measurement to be more suitable, or do not assign either of the two methods reliably high accuracy.
Individual evidence
- ↑ Sonographic amniotic fluid measurement, limit values, advantages and disadvantages of both methods, accessed July 26, 2013
- ↑ AFI table , accessed July 26, 2013.
- ↑ AF Nabhan, YA Abdelmoula: Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome . Cochrane Collaboration , July 8, 2009, doi: 10.1002 / 14651858.CD006593.pub2
- ↑ CJ Jeng, TJ Jou, KG Wang, YC Yang, YN Lee, CC Lan: Amniotic fluid index measurement with the four-quadrant technique during pregnancy . PMID 2198348
- ↑ EF Magann, SP Chauhan, PS Barrilleaux, NS Whitworth, JN Martin: Amniotic fluid index and single deepest pocket: weak indicators of abnormal amniotic volumes . PMID 11042310
