Yagel S, Adoni A, Oman S, Wax Y, Hochner-Celnikier D
Br J Obstet Gynaecol. 1986 Feb;93(2):109-15. doi: 10.1111/j.1471-0528.1986.tb07874.x.
The use of femur length (FL) and biparietal diameter (BPD) for estimation of gestational age (GA) was investigated using 1123 ultrasound measurements between the 14th and 41st week of gestation. Femur length was found to provide a more accurate index than BPD for the entire range of gestational age considered. If an interval of approximately +/- 2.5 weeks is considered 'satisfactory', the accuracy of FL past the 31st week is not sufficient to justify its use. Combining the FL and BPD measurements via the formula: GA = 9.565 + (0.0414) FL + (0.0024573) FL2 + (0.15209) BPD - (0.00015827) BPD2 provides an index of gestational age accurate to approximately +/- 2.5 weeks up to the 32nd week of gestation and accurate to approximately +/- 2.75 weeks up to the 34th week of gestation. This is the first time that combining FL and BPD in a statistically rigorous manner has been proposed as an index of gestational age, and we suggest that this combination be used as a routine tool in its assessment.
利用妊娠14至41周期间的1123次超声测量，研究了使用股骨长度（FL）和双顶径（BPD）来估计孕周（GA）的情况。结果发现，在整个所考虑的孕周范围内，股骨长度比双顶径能提供更准确的指标。如果将大约±2.5周的区间视为“令人满意”，那么在31周之后股骨长度的准确性就不足以证明其使用的合理性。通过公式GA = 9.565 + (0.0414) FL + (0.0024573) FL2 + (0.15209) BPD - (0.00015827) BPD2 将股骨长度和双顶径测量值相结合，在妊娠32周之前可提供一个孕周指标，其准确性约为±2.5周，在妊娠34周之前准确性约为±2.75周。这是首次以统计学严谨的方式提出将股骨长度和双顶径相结合作为孕周指标，我们建议在孕周评估中使用这种组合作为常规工具。
