A new formula for estimating gestational age by crown-rump length

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Biostatistics

Background:

• Accurate estimation of gestational age via ultrasound is vital for prenatal care and monitoring fetal development.
• Existing formulas may lack accuracy due to evolving maternal demographics and ultrasound technology.

Purpose of the Study:

• To develop novel formulas for calculating gestational age from first-trimester ultrasound measurements.
• To compare the accuracy of these new formulas against established methods.

Main Methods:

• Retrospective observational study of 1436 in vitro fertilization pregnancies with known embryo transfer dates.
• Polynomial regression analysis to model the relationship between crown-rump length and gestational age.
• Evaluation of models based on systematic error, random error, absolute difference, and accuracy within 0-2 days.

Main Results:

• Three models (linear, cubic, quadratic) were developed, with the cubic model showing the highest correlation coefficient (0.991).
• The new cubic formula demonstrated superior performance, exhibiting lower systematic error (0.06%), random error (2.43%), and mean absolute difference (0.97 days).
• The new formula achieved a higher proportion of estimations within 0-2 days (93.5%) compared to previous formulas.

Conclusions:

• A novel cubic formula derived from first-trimester crown-rump length provides more accurate gestational age estimation.
• This improved accuracy is crucial for optimizing prenatal care and fetal development monitoring.