刘筱玫医生10月19日主题帖:孕7周查血可知宝宝性别
前几天，在“意大利你问我答”版块里，有准妈妈们问我关于在B超辨别出胎儿性别之前，通过采样母亲血来查胎儿性别的检查。在中国，很多人包括很多资深的妇科专家认为这是天方夜谭。实际上，这项技术确实存在， 这种检查是从孕7周开始就可以查出胎儿性别。在意大利，MILANO，ROMA，FIRENZE，GENOVA等这几个城市都可以作，但造价高。
2011年就出现此项技术的相关新闻，原文如下，帮助大家探索此项技术的奥秘。
Non invasive Fetal Sex Determination Using Cell-Free Fetal DNA
Stephanie A. Devaney, PhD; Glenn E. Palomaki, PhD; Joan A. Scott, MS, CGC; Diana W. Bianchi, MD.这项技术的主要实现者为美国的 Stephanie A. Devaney AMA. 2011;306(6):627-636. doi:10.1001/jama.2011.1114.
Context Non invasive prenatal determination of fetal sex using cell-free fetal DNA无创的产前检测母亲血中游离的胎儿DNA来确定胎儿性别，DNA provides an alternative to invasive techniques for some heritable disorders. In some countries this testing has transitioned to clinical care, despite the absence of a formal assessment of performance.
Objective To document overall test performance of noninvasive fetal sex determination using cell-free fetal DNA and to identify variables that affect performance. Data Sources Systematic review and meta-analysis with search of PubMed (January 1, 1997-April 17, 2011) to identify English-language human studies reporting primary data. References from review articles were also searched.
Study Selection and Data Extraction Abstracts were read independently to identify studies reporting primary data suitable for analysis. Covariates included publication year, sample type, DNA amplification methodology, Y chromosome sequence, and gestational age. Data were independently extracted by 2 reviewers.
Conclusions Despite interstudy variability, performance was high using maternal blood. Sensitivity and specificity for detection of Y chromosome sequences was greatest using RTQ-PCR after 20 weeks' gestation. 通过母亲血液检查来寻找男性胎儿Y染色体，在孕20周后使用RTQ-PCR分析有最大的敏感度特异度，Tests using urine and tests performed before 7 weeks' gestation were unreliable. 孕7周之前母亲尿检或血液检查都无法查出。
Non invasive prenatal determination of fetal sex could provide an important alternative to invasive cytogenetic determination, which is currently the gold standard for ambiguous genitalia, X-linked conditions, and single-gene disorders such as congenital adrenal hyperplasia. Chorionic villus sampling and amniocentesis have small but measurable rates of procedure-related pregnancy loss. The availability of a reliable noninvasive alternative to determine fetal sex would reduce unintended fetal losses and would presumably be welcomed by pregnant women carrying fetuses at risk for disorders. A much broader potential application for fetal sex detection is family balancing, which poses ethical concerns.
Fetal sex determination can be performed by ecography at as early as 11 weeks' gestation , although not reliably 孕11周通过超声就可以查胎儿性别, 尽管不总是可靠. Test performance across published studies varies significantly. According to a review by Odeh et al, fetal sex cannot be determined by ultrasound examination in 7.5% to 50% of pregnancies at 11 weeks' gestation, and this decreases to 3% to 24% at 13 weeks. When reported, the sex determination is incorrect as often as 40% of the time at 11 weeks, although by 13 weeks, accuracy (when reported) is close to 100%. 根据Odeh等学者的说法，孕11周有7.5% 到 50%的胎儿性别不能被B超识别，孕13周这个数字会降低到3% 到 24%。据报道，孕11周验错率可以达到40%，而到了孕13周准确率会接近100%。
The presence of cell-free circulating Y chromosome DNA sequences in the plasma of pregnant women was first described in 1997. 1997年首次描述母亲血浆中可能出现男性胎儿游离的Y性染色体DNA序列。 Since that report, many groups worldwide have validated the initial finding that Y chromosome sequences can be amplified and used to identify male fetuses. 从那时起，世界范围内很多研究机构组织团体开始尝试通过生物技术放大这些微量的Y染色体序列来识别男性胎儿。
The research has been extended using a variety of methodologies, sex-specific markers, and sample types across all gestational ages. In countries such as the Netherlands, the United Kingdom, France, and Spain, this testing has already transitioned to routine clinical care despite the absence of a formal assessment of its performance. More recently, companies have begun offering this technology directly to the consumer over the Internet. 在荷兰，英国，法国，西班牙等国，这项通过母亲血液早期识别胎儿性别的检查已经成为很常见的临床检查， 而并没有对它带来的影响男女平衡等一系列问题进行后果的评估。最近，互联网上有些机构对消费者直接提供此项检查的服务。
NOTA： 准妈妈们如果想在米兰作这项7周就知道性别的抽血检查，可以直接联系我电子邮件或诊所中文预约电话。 刘医生 | 
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发表于 2014-1-13 21:40:38
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