Impact of replacing Chinese ethnicity‐specific fetal biometry charts with the INTERGROWTH‐21st standard

• Published in: BJOG : an international journal of obstetrics and gynaecology Vol. 123; no. S3; pp. 48 - 55
• Main Authors: Cheng, YKY, Leung, TY, Lao, TTH, Chan, YM, Sahota, DS
• Format: Journal Article
• Language: English
• Published: London Wiley Subscription Services, Inc 01-09-2016
• Subjects: Chinese; fetal biometry; INTERGROWTH‐21st; pregnancy; small‐for‐gestational‐age; ultrasound measurements
• ISSN: 1470-0328; 1471-0528
• DOI: 10.1111/1471-0528.14008

Objective
To assess the impact of adopting the INTERGROWTH‐21st biometry standards in a Chinese population.
Design
Retrospective cohort study.
Setting
A teaching hospital in Hong Kong.
Population
A total of 10 527 Chinese women with a singleton pregnancy having a second‐ or third‐trimester fetal anomaly or growth scan between January 2009 and June 2014.
Methods
Z‐scores were derived for fetal abdominal circumference (AC), head circumference (HC), and femur length (FL) using the INTERGROWTH‐21st and Chinese biometry standards. Pregnancies with aneuploidy, structural or skeletal abnormalities, or that developed pre‐eclampsia were excluded. Z‐scores were stratified as <2.5th, <5th, <10th, >90th, >95th, or >97.5th percentile. Birthweight centile, adjusted for gestation and gender, was categorised as ≤3rd, 3rd to ≤5th, 5th to ≤10th, and >10th. Pairwise comparison and the McNemar test were performed to assess biometry Z‐score differences and concordance between the INTERGROWTH‐21st and Chinese standards.
Main outcome measures
The sensitivity of both the local and INTERGROWTH‐21st AC standards to identify pregnancies that were small‐for‐gestational‐age (SGA) was assessed.
Results
INTERGROWTH‐21st AC, HC, and FL Z‐scores were significantly lower than those obtained using our local reference for AC, HC, and FL (P < 0.0001 for all). The proportion of fetuses with biometry in the <2.5th, <5th, <10th, >90th, >95th, or >97.5th percentiles was statistically significant (P < 0.01 for all). A total of 1224 (15.5%) of the scans at 18–22 weeks of gestation had AC, HC, or FL below the 3rd percentile of the INTERGROWTH‐21st standard.
Conclusions
Adopting the INTERGROWTH‐21st standard would lead to a significant number of fetuses being at risk of misdiagnosis for small fetal size, particularly when using HC and FL measures.
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INTERGROWTH‐21st biometry assessment in Chinese leads to fetuses being at risk of misdiagnosis of small fetal size.
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INTERGROWTH‐21 biometry assessment in Chinese leads to fetuses being at risk of misdiagnosis of small fetal size.
摘要
改用INTERGROWTH‐21st 标准对中国胎儿生长评估的影响
目的
探讨在中国人群中采用INTERGROWTH‐21st生长参数标准的影响
设计
回顾性队列研究
设置
香港一所教学医院
人口
10,527名怀有单胎妊娠华裔孕妇于2009年1月至2014年6月期间进行孕中、晚期胎儿超声检查
方法
根据INTERGROWTH‐21st 和中国人群标准得出的腹围 (AC)、头围 (HC) 及股骨长 (FL) 的Z 评分值。非整倍体、结构或骨骼异常胎儿或有子痫前期的孕妇都被排除。Z 评分值分为 <2.5、 <5、 <10、 >90、 >95 或>97.5 百分位。经孕周和性别调整后的出生体重百分位数被归类为 ≤3、第3至 ≤5、第5至 ≤10和 >10百分位。用两两比较和McNemar检验来评估 INTERGROWTH‐21st和中国生物测量标准的Z 评分值的差异和一致性。
主要结局指标
评估中国人群和INTERGROWTH‐21st 腹围标准对确定小于胎龄儿 (SGA) 的灵敏度。结果:INTERGROWTH‐21st AC、HC和FL 的Z 评分值均显著降低 (一律是P <0.0001)。胎儿在生物测量 ‘<2.5’, ‘<5’, ‘<10’, ‘>90’, ‘>95’ 或 ‘>97.5’ 百分位之比例是显著的 (一律是P <0.01)。1224 (15.5%) 例18至22周超声数据的AC、HC或FL是低于INTERGROWTH‐21st 标准的第3百分位。
结论
采用INTERGROWTH‐21st 标准,尤其当使用HC和FL的时候,将显著增加对小胎儿误诊的风险。