gynecology and obstetrics
Oligohydramnios
Diagnosis of Oligohydramnios
Ultrasonographic measurement of amniotic fluid volume Comprehensive ultrasonographic examination, including evaluation for fetal malformations Testing for clinically suspected maternal causes Oligohydramnios may be suspected if uterine size is less than expected for dates or if fetal movements are decreased; it may also be suspected based on incidental ultrasonographic findings. However, qualitative estimates of amniotic fluid volume tend to be subjective. If oligohydramnios is suspected, amniotic fluid should be assessed quantitatively using the amniotic fluid index (AFI) or single deepest pocket (SDP). The volume of amniotic fluid cannot be measured directly. Thus, excessive fluid is defined indirectly using one of the following ultrasonographic criteria: AFI ≤ 5 cm: AFI is the sum of the vertical depth of fluid measured in each quadrant of the uterus; normal AFI ranges from > 5 to < 24 cm. SDP < 2 cm: SDP is a measurement of the deepest pocket of amniotic fluid; normal SDP is ≥ 2 to < 8 cm. It appears that neither AFI nor SDP is superior to the other in terms of preventing adverse perinatal outcomes. Each has limitations: AFI often results in overdiagnosis of oligohydramnios; SDP results in overdiagnosis of polyhydramnios ( Diagnosis references , If oligohydramnios is diagnosed, clinicians should check for possible causes, including premature rupture of membranes. Comprehensive ultrasonographic examination is done to check for fetal malformations and any evident placental causes (eg, placental abruption). Clinicians can offer amniocentesis and fetal karyotyping if ultrasonography suggests fetal malformations or aneuploidy. If uteroplacental insufficiency is suspected and intrauterine growth restriction is detected, the umbilical artery is assessed using Doppler ultrasonography. 1.Kehl S, Schelkle A, Thomas A, et al: Single deepest vertical pocket or amniotic fluid index as evaluation test for predicting adverse pregnancy outcome (SAFE trial): A multicenter, open-label, randomized controlled trial.Ultrasound Obstet Gynecol47 (6):674–679, 2016. doi: 10.1002/uog.14924 2.Nabhan AF, Abdelmoula YA: Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome.Cochrane Database Syst Rev2008 (3):CD006593, 2008. 