Amniotic Fluid Volume Assessment: Eight Lessons Learned

Everett F Magann,1 Julie R Whittington,1 John C Morrison2 ,†Suneet P Chauhan3 1Departments of Obstetrics and Gynecology of the University of Arkansas for the Medical Sciences, Little Rock, AR, USA; 2Department of Obstetrics and Gynecology of the University of Mississippi Medical Center, Jackson, MS, USA; 3Department of Obstetrics, Gynecology and Reproductive Sciences of the University of Texas Health Sciences Center at Houston, Houston, TX, USA†Dr John C. Morrison passed away on September 1, 2019Correspondence: Everett F MagannDepartment of Obstetrics and Gynecology of the University of Arkansas for the Medical Sciences, 4301 W. Markham St. Slot # 518, Little Rock, AR, 72205, USATel +1 501-686-8345Fax +1 501-526-7820Email efmagann@uams.eduAbstract: Actual AFV can be determined by a dye-dilution technique or be directly measured at cesarean. This allows investigators to correlate estimated and actual AFVs. Lessons learned by assessing the relationship of estimated to actual AFVs. 1) Ultrasound estimates normal actual AFVs well, but abnormal AFVs poorly. 2) Quantile regression is a better statistical methodology to create a normal AFV curve across pregnancy. 3) There is no difference in the accuracy of the subjective (visualization without measurements) compared with the objective (visualization with measurements) technique in identifying normal and abnormal AFVs. 4) Color Doppler use leads to the over-diagnosis of oligohydramnios. 5) Intravenous hydration increases actual AFVs. 6) The estimation of AFV can be done with the transducer held perpendicular to the floor or perpendicular to the uterine contour. 7) The single deepest pocket should be used for identifying low AFVs. 8) The AFI should be used for identifying high AFVs.Keywords: amniotic fluid volume, oligohydramnios, polyhydramnios, color Doppler, subjective assessment, objective assessment