Association between amniotic fluid evaluation and fetal biometry: a prospective French "Flash" study

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Diagnostic Ultrasound

Background:

• Accurate assessment of amniotic fluid volume is crucial for fetal well-being.
• Several methods exist for quantifying amniotic fluid, including subjective assessment (SM), deepest vertical pocket (DVP), and amniotic fluid index (AFI).
• The relationship between these methods and estimated fetal weight (EFW) requires further clarification, considering maternal and fetal factors.

Purpose of the Study:

• To investigate the association between SM, DVP, and AFI with EFW (percentile or Z-score).
• To adjust for maternal-fetal parameters in the analysis.
• To compare the influence of maternal-fetal factors on DVP and AFI.

Main Methods:

• Nationwide cross-sectional study in France.
• Inclusion of low-risk singleton pregnancies (18-40 weeks).
• Data collected using the "flash" study method by 65 sonographers on 1667 scans; crude and adjusted odds ratios computed.

Main Results:

• EFW Z-score significantly associated with SM in both trimesters.
• In the 2nd trimester, EFW Z-score and male fetal gender associated with DVP and AFI.
• In the 3rd trimester, EFW Z-score, LGA/SGA status, maternal overweight, and class I obesity associated with AFI and DVP.

Conclusions:

• All three methods (SM, DVP, AFI) for amniotic fluid assessment are significantly associated with EFW.
• DVP and AFI show similar performance, but DVP is more influenced by maternal-fetal factors.