https://orcid.org/0000-0001-6823-7635
Abstract
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.
Acknowledgments
We thank Donna G. Eastham, BA CRS, for her help in editing, formatting and submitting this manuscript. In memoriam and posthumously submitted by Dr. John C. Morrison, who passed away on Sept 1, 2019. He made significant contributions to the paper in literature review, study design, and manuscript drafting.
Disclosure
Dr. Magann was the co-editor of the chapter on the ultrasound assessment of amniotic fluid volume (Oligohydramnios) and received royalties from UpTo Date. The authors report no other conflicts of interest in this work.