Incidence of chromosome abnormalities at a second-trimester genetic amniocentesis for Mainland Chinese women of advanced maternal age:a study of 6,584 cases

Objective:The aim of this study was to calculate the expected incidence of chromosomal aneuploidy at second trimester genetic amniocentesis in China's Mainland in women aged 35 and older. Methods:We reviewed the genetic amniocenteses data in Peking Union Medical College Hospital between January 2001 to June 2011.The indication for genetic amniocentesis was solely advanced maternal age(AMA).A total of 6,584 cases were included in this study.The AMA women was divided into two groups by maternal age,the group of 35-39 years old and the group of≥40 years old.The incidence of fetal Down syndrome was compared between the two groups by chi-square test. Results:A total of 121 cases were diagnosed to be chromosomally abnormal,giving an overall incidence of 18.38‰(121/6,584).The abnormal karyotypes included 111 cases of various aneuploidies and 10 cases with various structural abnormalities.The aneuploidies(mosaicism included) were 59 cases of(47,+ 21),25 cases of (47,+ 18),2 cases of(47,+ 13),8 cases of(45,X),3 cases of(47,XXX),13 cases of(47,XXY) and 1 case of(47,XYY).The karyotype of(47,+21) was the most frequent chromosomal abnormality,with an overall incidence of 8.96‰,account for 53.1%of all aneuploidies.Sex chromosome aneuploidies were the next most common,with a total incidence of 3.80‰.The incidence of fetal Down syndrome was significantly higher in the group of≥40 years old than that of the group of 35-39 years old(P = 0.047). Conclusions:The incidence of chromosomal aneuploidy found in this study is the first data published for China's Mainland and will be helpful for the counseling of pregnant women in this age group.Consideration may be given to prenatal screening versus prenatal diagnosis in women of advanced maternal age in China's Mainland.

Genetic counseling, prenatal screening and diagnosis of Down syndrome in the second trimester in women of advanced maternal age： a prospective study

Background The incidence of autosomal trisomy in livebirths is strongly dependent on maternal age. Special consideration is given to the provision of prenatal screening and cytogenetic testing to women of advanced maternal age （AMA）. The aim of this study was to evaluate the effectiveness of second trimester prenatal screening and amniocentesis for Down syndrome （DS） and compare the trends of choice of screening and amniocentesis among AMA women. Methods A total of 5404 AMA patients with natural singleton pregnancy were recruited for this prospective study from January 2008 to December 2010. The gestational weeks were from 15 weeks to 20~6 weeks. The patients referred were grouped into a screening group （2107 cases） and an amniocentesis group （3297 cases） by their own decision. The prevalence of DS was compared between the two groups by chi-square test. Choice rates for each maternal age with trends were compared by regression analysis. Results There were 18 cases of fetal DS detected in the screening group with a prevalence of 8.54%o （18/2107）. Twenty- five cases of fetal DS were diagnosed in the amniocentesis group with a prevalence of 7,58%0 （25/3297）. No statistical difference was observed in the prevalence of DS between the screening and amniocentesis group （P=0.928）. The invasive testing rate for DS in the amniocentesis group was 5.54 times higher than that of the screening group （1/131.88 vs. 1/23.78）. With the increase of the maternal age, the choice of amniocentesis increased while the choice of the screening showed an opposite trend. The choice of the AMA women between the screening and amniocentesis was significantly age relevant （P=0.012）. Conclusions The second trimester serum screening age alone to screen for DS. We suggest educating screening and amniocentesis options. in combination with maternal age was more effective than maternal the patients by recommending AMA women be informed of both

高龄孕妇唐氏综合征血清学筛查的价值

目的研究高龄孕妇(≥35岁)血清学筛查唐氏综合征的价值,以期减少羊膜腔穿刺的几率,避免医源性流产。方法对在复旦大学附属妇产科医院产检的10601名中期妊娠孕妇进行唐氏综合征的血清学筛查,采用血清学三联指标,即绒毛膜促性腺激素、非结合雌三醇、甲胎蛋白。通过Beckman公司的放射免疫仪测定计算上述三项指标的MoM值和唐氏综合征的患病风险。以1/380为切割值,并随访所有孕妇的妊娠结局。结果从2007年6月～2009年12月,共有10601名在复旦大学附属妇产科医院产检的适龄孕妇进行唐氏综合征的血清学筛查,高风险孕妇有899例,总的阳性率为8.48%。其中高龄孕妇有777例,其高风险例数有268例,阳性率为34.49%,明显高于年龄低于35岁的阳性风险率,后者为6.42%。在随访结果中,共有9例唐氏儿,其中4例为高龄孕妇所生。这4例唐氏综合征的血清学检查结果均为高风险,高龄孕妇的血清学筛查阴性结果中,没有出现唐氏儿。结论对于高龄孕妇,血清学筛查可作为第一线筛查手段,应与孕妇及家属探讨产前筛查的方法及各自利弊,由孕妇及家属决定是否直接接受羊膜腔穿刺。