Impact of replacing C hinese ethnicity‐specific fetal biometry charts with the INTERGROWTH ‐21 st 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: 01-09-2016
• ISSN: 1470-0328; 1471-0528
• DOI: 10.1111/1471-0528.14008

Objective
To assess the impact of adopting the
INTERGROWTH
‐21
st
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
‐21
st
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
‐21
st
and Chinese standards.
Main outcome measures
The sensitivity of both the local and
INTERGROWTH
‐21
st
AC
standards to identify pregnancies that were small‐for‐gestational‐age (SGA) was assessed.
Results
INTERGROWTH
‐21
st
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
‐21
st
standard.
Conclusions
Adopting the
INTERGROWTH
‐21
st
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.
Tweetable abstract
INTERGROWTH‐21
st
biometry assessment in Chinese leads to fetuses being at risk of misdiagnosis of small fetal size.
Tweetable abstract
INTERGROWTH
‐21 biometry assessment in Chinese leads to fetuses being at risk of misdiagnosis of small fetal size.
摘要
改用INTERGROWTH‐21
st
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‐21
st
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
‐21
st
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
‐21
st
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
‐21
st
腹围标准对确定小于胎龄儿 (
SGA
) 的灵敏度。结果:
INTERGROWTH
‐21
st
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
‐21
st
标准的第3百分位。
结论
采用INTERGROWTH‐21
st
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。