Amniotic fluid index in twin gestation

Area of Science:

• Maternal-Fetal Medicine
• Obstetrics
• Fetal Ultrasound

Background:

• Twin gestations present unique challenges in monitoring fetal well-being.
• Accurate assessment of amniotic fluid volume is crucial for fetal health.
• Existing methods for amniotic fluid index (AFI) may require adaptation for twin pregnancies.

Purpose of the Study:

• To describe a novel methodology for calculating a two-pocket amniotic fluid index (AFI) for each fetus in twin gestations.
• To establish normative reference ranges for twin AFI throughout gestation.
• To assess the variability associated with the twin AFI measurement.

Main Methods:

• A retrospective analysis of 216 pairs of two-pocket AFI measurements from twin gestations was conducted.
• Regression analysis was used to generate curves for overall twin AFI, as well as for the larger and smaller AFI within each twin pair.
• Intrasonographer, intersonographer, within-mother, and between-mother variations were quantified.

Main Results:

• The twin AFI demonstrated a non-linear increase up to 27 weeks of gestation.
• From 27 to 36 weeks, a decreasing linear trend was observed for the twin AFI.
• Confidence limits were plotted for all three derived AFI curves based on variation estimates.

Conclusions:

• The described two-pocket AFI methodology provides a standardized approach for assessing amniotic fluid in twin pregnancies.
• The established reference curves offer valuable insights into normal AFI progression in twins.
• Understanding measurement variability is essential for accurate interpretation and clinical application of the twin AFI.