Sonar Measurement of Fetal Crown-Rump Length as Means of Assessing Maturity in First Trimester of Pregnancy

Correlation of first‐trimester fetal crown–rump length with outcome of pregnancy and birth weight

“…The measurement allows the obstetrician to calculate gestational age with accuracy from the 6th to the 14th gestational week [6].…”

The value of adding a universal booking scan to an existing protocol of routine mid‐gestation ultrasound scan

“…The nursing staff used a published algorithm to calculate the clinically estimated GA by comparing the LMP history with abdominal findings at the booking visit [13]. The ultrasound-based GA was derived from biometric parameters (including crown-rump length, biparietal diameter, head circumference [HC], abdominal circumference [AC], and femur length) by calculating the average GA from these measurements-provided obvious fetal anomalies were excluded and the GA from all variables were within 8 days of each other [14][15][16][17]. The original expected date of delivery (EDD) was changed if the ultrasound-based GA differed significantly (discrepancy >2 standard deviations before 16 weeks; >2 weeks at 16-24 weeks; and >3 weeks beyond 24 weeks).…”

Morphological and functional evaluation of normal and abnormal fetal growth by ultrasonography

“…This is because CRL measurement during this period shows the least amount of difference between fetuses compared with other parameters such as BPD, FL or AC [2]. Ultrasound determination of fetal CRL in the first trimester of pregnancy was introduced by Robinson [3]. Robinson and Fleming [4] showed that fetal age could be estimated to within ± 4.7 days from a single CRL measurement.…”