Dating biometry during the first trimester: accuracy of an every-day practice

Area of Science:

• Maternal-Fetal Medicine
• Diagnostic Ultrasound
• Embryology

Background:

• Accurate gestational dating is crucial for optimal pregnancy management.
• First-trimester ultrasound is a common method for estimating gestational age.

Purpose of the Study:

• To evaluate the accuracy of routine clinical practice for determining gestational age using greatest embryonic length (GEL) ultrasound measurements.
• To compare the effectiveness of different embryonic growth curves for dating pregnancies.

Main Methods:

• Retrospective analysis of first-trimester ultrasound measurements from in-vitro fertilization (IVF) pregnancies.
• Comparison of seven different embryo growth curves using 257 measurements from 143 patient files.
• Calculation of 95% prediction intervals to assess the precision of each curve in dating pregnancies.

Main Results:

• The Robinson and Wisser embryo growth curves demonstrated the highest accuracy for GEL measurements between 3 and 80 mm.
• The 95% prediction intervals for these curves were 9.5 and 10.2 days, respectively.
• This indicates a high degree of precision in dating pregnancies within this range.

Conclusions:

• Greatest embryonic length (GEL) ultrasound measurements in routine clinical practice provide accurate gestational dating.
• The accuracy achieved is comparable to that of more controlled prospective studies.
• The Robinson and Wisser curves are recommended for clinical use in dating pregnancies via GEL.