Research Article
Ultrasound Reference Chart Based on IVF Dates to Estimate Gestational Age at 6–9 weeks’ Gestation
Table 1
Approaches used by six previous studies to generate CRL reference charts.
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Scan: type of ultrasound scanner used, technique: technique used for scanning, TA: transabdominal, TV: transvaginal, RT: real time, LMP: last menstrual period, IVF: in vitro fertilisation. *n represents the number of observations, number of patients in brackets if this is different to number of observations. |