Abstract:
Objective To explore the clinical significance of non-invasive prenatal testing(NIPT)for fetal chromosomal abnormalities in the cases of twin pregnancy and its relationship with age and other related factors.Methods A total of 3733 women with twin pregnancy of 12-26+6 weeks who voluntarily underwent NIPT in the Ningbo Women and Children\'s Hospital from January 2018 to December 2022 were selected.The results of NIPT and amniocentesis were compared and all the participants were followed up.The detection rate of chromosomal abnormalities by NIPT was calculated,and its correlations with age,gestational weeks,chorionicity,and pregnancy type were analyzed.Results Among the 3733 cases,71 cases of fetal chromosome abnormality were indicated by NIPT,including 13 cases of trisomy 21,19 cases of trisomy 18,5 cases of trisomy 13,18 cases of sex chromosome abnormality,and 16 cases of chromosome microdeletion/duplication(excluding 21,18,13,and sex chromosomes),among which 34 cases were true positive and 37 cases were false positive.The overall sensitivity,specificity,and positive predictive value(PPV)of NIPT for chromosomal abnormalities in the cases of twin pregnancy were 100%,98.99%,and 47.89%(34/71),respectively.NIPT showed the sensitivity,specificity,and PPV of 100%,99.78%,and 78.38%(29/37)for trisomy 21,18,and 13,100%,99.56%,and 16.67%(3/18)for sex chromosome abnormalities,and 100%,99.62%,and 12.5%(2/16)for chromosome microdeletion/duplication,respectively.In the age group of ≥40 years,the NIPT for chromosomal abnormalities showed the PPV of 66.67%,the sensitivity of 100%,and the misdiagnosis rate of 30%。However,the NIPT for trisomy 21,18,and 13 showed the PPV of 100%,the misdiagnosis rate of 0,and the sensitivity and specificity of 100%.In terms of grouping based on gestational weeks,the NIPT for chromosomal abnormalities showed the highest PPV(51.28%)in the women with twin pregnancy for 14-17+6 weeks,followed by that(50.00%)in the women with twin pregnancy for 22-26+6 weeks;the NIPT for trisomy 21,18,and 13 showed the highest PPV of 94.74% in the gestation group of 14-17+6 weeks,followed by that(83.33%)in the gestation group of 18-21+6 weeks.The rate of dichorionic diamniotic twins was higher in assisted pregnancies than in natural pregnancies,and NIPT showed the same detection efficiency for dichorionic diamniotic twins and monochorionic diamniotic twins and the same detection efficiency for different pregnancy types.Conclusions NIPT has high accuracy in the diagnosis of twin pregnancy and high sensitivity and high specificity for different ages and gestational weeks,especially for trisomy 21,18,and 13.NIPT is suitable for assisted pregnancy and natural pregnancy,and it is of high value in clinical application.However,extensive application needs a large population-based study.
目的 初步探讨无创产前筛查(NIPT)在双胎染色体异常筛查的价值及其与年龄等相关因素的关系。方法 选取2018年1月至2022年12月在宁波市妇女儿童医院自愿接受NIPT检测的3733例(孕12~26+6周)双胎孕妇,回顾其NIPT及羊水穿刺结果,并对所有研究对象进行随访。计算NIPT对染色体异常的检出率,分析其与年龄、孕周、绒毛膜性及受孕类型的相关性。结果 3733例双胎中,NIPT提示胎儿染色体异常的有71例,包括13例T21、19例T18、5例T13、18例性染色体异常及16例染色体微缺失/重复(21、18、13及性染色体除外),其中真阳性34例,假阳性37例。NIPT对双胎染色体异常的总体灵敏度为100%,特异度为98.99%,阳性预测值(PPV)为47.89%(34/71);对T21、18、13总的灵敏度为100%,特异度为99.78%,PPV为78.38%(29/37);对性染色体的灵敏度为100%,特异度为99.56%,PPV为16.67%(3/18);对染色体微缺失/重复的灵敏度为100%,特异度为99.62%,PPV为12.5%(2/16)。以年龄分组,在总染色体中,NIPT在≥40岁组中的PPV达66.67%,灵敏度为100%,但误诊率也达30%;而在T21、18、13中,NIPT在≥40岁组中的PPV达100%,误诊率为0,灵敏度及特异度均为100%。以孕周分组,在总染色体中,孕14~17+6周组的PPV最高(51.28%),其次为孕22~26+6周组(50.00%);在T21、18、13中,孕14~17+6周组最高(94.74%),其次为孕18~21+6周组(83.33%)。双绒毛膜双羊膜囊双胎的比率在辅助妊娠中高于自然妊娠,NIPT对双绒毛膜双羊膜囊双胎及单绒毛膜双羊膜囊双胎均有相同的检出效率,对不同受孕类型也具有相同的检出效率。结论 初步发现NIPT在双胎中具有较高的准确性,对不同年龄、孕周都具有高敏感性和高特异性的优点,尤其是T21、18、13。NIPT适用于辅助妊娠及自然受孕,具有较高的临床应用价值,但广泛应用还需大人群基数研究。.