de Paco Matallana C, Rolle V, Fidalgo A M, Sánchez-Romero J, Jani J C, Chaveeva P, Delgado J L, Santacruz B, Nicolaides K H, Gil M M
Department of Obstetrics and Gynecology, Hospital Clínico Universitario 'Virgen de la Arrixaca', El Palmar, Murcia, Spain; Institute for Biomedical Research of Murcia, IMIB-Arrixaca, El Palmar, Murcia, Spain.
Faculty of Medicine, Universidad de Murcia, Murcia, Spain.
Ultrasound Obstet Gynecol. 2025 May;65(5):560-566. doi: 10.1002/uog.29216. Epub 2025 Apr 3.
To evaluate the accuracy of fetal biparietal diameter (BPD) measurement in comparison with crown-rump length (CRL) measurement for pregnancy dating at 11-13 weeks' gestation.
This was a retrospective multicenter cohort study performed in five maternity units in Spain, the UK, Belgium and Bulgaria between January 2011 and December 2019. We included all women who attended a routine ultrasound examination at 11 + 0 to 13 + 6 weeks who had a singleton pregnancy with a viable non-malformed fetus/neonate and ultrasound-derived measurements for both CRL and BPD, along with a comprehensive record of pregnancy outcomes. We developed a formula for pregnancy dating based on BPD using data from pregnancies conceived via in-vitro fertilization (IVF) by applying a simple linear regression. We validated this formula both internally and externally and compared it with the most commonly used formulae (Robinson's CRL-based and Kustermann's BPD-based formulae) through utilization of the Euclidean distance, relative absolute error and mean squared error. We also examined the rate of induction of labor for post-term pregnancy based on dating using each of the formulae.
A total of 49 492 women were included in the study, comprising 47 223 (95.4%) who conceived spontaneously and 2269 (4.6%) who conceived via IVF. In the internal validation performed using data from IVF pregnancies, our newly developed formula showed no significant difference when compared with the true gestational age calculated using conception date, with a mean difference of 0.0006 (95% CI, -0.09 to 0.09) days. In contrast, the mean difference of Kustermann's BPD-based formula was -0.31 (95% CI, -0.46 to -0.17) days and the mean difference of Robinson's CRL-based formula was -1.78 (95% CI, -1.88 to -1.68) days. In the external validation using data from spontaneously conceived pregnancies, with dating using Robinson's formula as the reference for 'true' gestational age, both our formula and Kustermann's formula resulted in underestimation of gestational age, with significant mean differences of -1.25 (95% CI, -1.28 to -1.22) days and -0.96 (95% CI, -0.98 to -0.93) days, respectively. The largest differences compared with Robinson's formula-based dating results were observed between 11 + 0 and 12 + 0 weeks. Dating the pregnancy using Robinson's formula led to 8.1% of pregnancies identified as requiring induction after 41 + 3 weeks, compared with 6.8% (P < 0.001) and 7.0% (P < 0.001) when applying our formula and Kustermann's formula, respectively.
Pregnancy dating based on ultrasound measurement of fetal BPD between 11 + 0 and 13 + 6 weeks' gestation is a reliable alternative to dating based on fetal CRL. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.
评估孕11至13⁺⁶周时，与头臀长（CRL）测量相比，胎儿双顶径（BPD）测量用于确定孕周的准确性。
这是一项回顾性多中心队列研究，于2011年1月至2019年12月在西班牙、英国、比利时和保加利亚的五个产科单位进行。我们纳入了所有在孕11⁺⁰至13⁺⁶周进行常规超声检查的单胎妊娠女性，其胎儿/新生儿存活且无畸形，并记录了CRL和BPD的超声测量值以及完整的妊娠结局记录。我们通过应用简单线性回归，利用体外受精（IVF）妊娠的数据，开发了一个基于BPD的孕周计算公式。我们在内部和外部对该公式进行了验证，并通过欧几里得距离、相对绝对误差和均方误差，将其与最常用的公式（基于Robinson的CRL公式和基于Kustermann的BPD公式）进行比较。我们还根据每个公式确定的孕周，检查了过期妊娠的引产率。
该研究共纳入49492名女性，其中47223名（95.4%）为自然受孕，2269名（4.6%）为IVF受孕。在使用IVF妊娠数据进行的内部验证中，我们新开发的公式与根据受孕日期计算的实际孕周相比，差异无统计学意义，平均差异为0.0006天（95%CI，-0.09至0.09）。相比之下，基于Kustermann的BPD公式的平均差异为-0.31天（95%CI，-0.46至-0.17），基于Robinson的CRL公式的平均差异为-1.78天（95%CI，-1.88至-1.68）。在使用自然受孕妊娠数据进行的外部验证中，以Robinson公式确定的孕周作为“实际”孕周的参考，我们的公式和Kustermann的公式均导致孕周估计值偏低，平均差异分别为-1.25天（95%CI，-1.28至-1.22）和-0.96天（95%CI，-0.98至-0.93）。与基于Robinson公式的孕周确定结果相比，最大差异出现在孕11⁺⁰至孕12⁺⁰周之间。使用Robinson公式确定孕周时，41⁺³周后有8.1%的妊娠被确定需要引产，而应用我们的公式和Kustermann的公式时，这一比例分别为6.8%（P<0.001）和7.0%（P<0.001）。
孕11⁺⁰至13⁺⁶周时，基于超声测量胎儿BPD确定孕周是一种可靠的替代基于胎儿CRL确定孕周的方法。©2025国际妇产科超声学会。
