Amniotic fluid assessment. Methods and role in fetal assessment

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Perinatal Surveillance

Background:

• Amniotic fluid volume (AFV) assessment is a common adjunct to nonstress testing for pregnancies requiring surveillance.
• Current clinical practice often involves evaluating AFV alongside nonstress tests for fetuses with maternal risk factors.

Purpose of the Study:

• To review the current literature and clinical applications of AFV assessment in high-risk pregnancies.
• To clarify the role of AFV assessment in conjunction with other antenatal testing methods.

Main Methods:

• Review of existing literature on amniotic fluid volume assessment techniques.
• Analysis of studies correlating AFV values with perinatal outcomes, particularly in postdate gestations.
• Comparison of quantitative and nonquantitative AFV assessment methods and ultrasonography versus dye-dilution techniques.

Main Results:

• Abnormal AFV values, by various methods, are associated with increased perinatal morbidity and mortality.
• Trends are most pronounced in postdate gestations.
• No single AFV assessment method has demonstrated consistent superiority over others in studies.
• Ultrasonography shows good correlation with dye-dilution but has limitations, especially at extreme AFV values.

Conclusions:

• Antenatal testing for at-risk fetuses should incorporate AFV evaluation.
• Fetuses with abnormal AFV, particularly when associated with other test abnormalities like a nonreactive nonstress test, require anatomical study and consideration for delivery.