A reassessment of biochemical marker distributions in trisomy 21-affected and unaffected twin pregnancies in the first trimester
A reassessment of biochemical marker distributions in trisomy 21-affected and unaffected twin pregnancies in the first trimester
复制标题
DOI：
10.1002/uog.8845
复制
发表时间：
2011-01-01
影响因子：
7.1
通讯作者：
Spencer, K.
中科院分区：
文献类型：
--
作者：
Madsen, H. N.;Ball, S.;Spencer, K.
目的探讨双胎妊娠与单胎妊娠两种生化指标妊娠相关血浆蛋白-a （ppap -a）和母体血清游离β -人绒毛膜促性腺激素（游离β - hcg）水平的差异，为双胎妊娠21三体等染色体异常筛查提供一种改进的方法。方法选取4843例未患病双胞胎和47例21型三体双胞胎。从孕龄8 ~ 14周，生成ppap - a和游离β - hcg的绒毛膜特异性中位数。计算每个生化标记物中位数的倍数。在有和没有生物化学的情况下，对包含颈部透明度和母亲年龄的筛查试验的检出率和假阳性率进行了估计。结果：在未受影响的妊娠中，单绒毛膜双胞胎和双绒毛膜双胞胎的两种生化标志物的中位数相对于单胎双胞胎的中位数显示出妊娠年龄特异性的增加。考虑到妊娠和绒毛膜性，患有21三体的双胎妊娠的游离β - hcg水平较高，而pap - a水平较低。使用1 / 100的固定风险临界值将生物化学纳入风险评估，使异卵双胞胎妊娠中胎儿21三体的检出率从78%提高到90%，假阳性率从8.0降低到5.9%。结论绒毛膜特异性生化标志物中值的产生及其在风险评估中的应用可将双胞胎早期染色体异常筛查的效果提高到与单胎妊娠相当的水平。ISUOG版权所有。约翰·威利父子有限公司出版。
Objective To estimate the difference between levels of the two biochemical markers pregnancy-associated plasma protein-A (PAPP-A) and maternal serum free beta-human chorionic gonadotropin (free beta-hCG) in twin pregnancies relative to singleton pregnancies and establish an improved screening procedure for chromosomal abnormalities such as trisomy 21 in twin pregnancies.Methods 4843 unaffected and 47 trisomy 21-affected twin pregnancies were included in the study. Chorionicity-specific medians were generated for PAPP-A and free beta-hCG from gestational ages 8 to 14 weeks. Multiple of the median values for each of the biochemical markers were calculated. Detection rates and false-positive rates were estimated for screening tests incorporating nuchal translucency and maternal age, with and without biochemistry.Results Medians for the two biochemical markers for monochorionic and dichorionic twins in unaffected pregnancies show a gestational age-specific increase relative to singleton medians. Allowing for gestation and chorionicity, twin pregnancies affected with trisomy 21 had higher levels of free beta-hCG and lower levels of PAPP-A. Adding biochemistry into the risk assessment using a fixed risk cut-off of 1 in 100 increased the detection rate for fetal trisomy 21 in dizygotic twin pregnancies from 78 to 90%, and decreased the false-positive rate from 8.0 to 5.9%.Conclusion Generation of chorionicity-specific medians for the biochemical markers and their use in risk assessment can improve the performance of first-trimester screening for chromosomal abnormalities in twins to a level comparable with that in singleton pregnancies. Copyright (C) 2010 ISUOG. Published by John Wiley & Sons, Ltd.