Prenatal Diagnosis and Counselling Clinic, Department of Obstetrics and Gynaecology, Kwong Wah Hospital, Kowloon, HKSAR, China.
Prenat Diagn. 2010 Nov;30(11):1094-9. doi: 10.1002/pd.2623.
To evaluate ultrasound scan and other prenatal screening tests for trisomy 18 in a regional obstetric unit and to review the management approach for women with positive trisomy 18 screening results.
Prenatal diagnosis databases were accessed to identify fetuses that had confirmed trisomy 18 karyotypes or were at high risk for trisomy 18 on second-trimester biochemical screening or first-trimester combined screening tests over a period of 10 years from 1 September 1997 to 30 September 2007.
Sixty-nine women were confirmed to have trisomy 18 fetuses by karyotyping either prenatally (n = 61) or postnatally/post-miscarriage (n = 8) during the study period. The detection rate of ultrasound scan ≤ 14 weeks and 18 to 21 weeks to detect trisomy 18 was 92.7 and 100%, respectively. A total of 80 and 87% of fetuses had two or more ultrasound abnormalities detected in the ≤ 14 weeks and 18 to 21 weeks anomaly scans, respectively. Forty-eight women screened positive for trisomy 18 by second-trimester biochemical screening with human chorionic gonadotrophin (hCG) and alpha fetoprotein (AFP). Only one was true positive (positive predictive value = 1/48 or 2%). Eleven women screened positive for trisomy 18 by first-trimester combined screening with nuchal translucency scan and maternal serum for pregnancy-associated plasma protein A (PAPP-A) and hCG between 11 and 13 + 6 weeks. Three were true positive (positive predictive value = 3/11 or 27%). All four cases with positive screening had ultrasound abnormalities.
Ultrasound scan for fetal anomalies is the most effective screening test for trisomy 18. A policy of conservative management for women with positive second-trimester biochemical screening or first-trimester combined screening for trisomy 18 is reasonable in the absence of ultrasound fetal abnormalities. Unnecessary invasive tests can be avoided.
评估区域产科单位中 18 三体综合征的超声扫描和其他产前筛查试验，并回顾对 18 三体综合征筛查阳性妇女的管理方法。
通过访问产前诊断数据库，确定了在 1997 年 9 月 1 日至 2007 年 9 月 30 日的 10 年期间，通过核型分析在产前（n=61）或产后/流产后（n=8）证实为 18 三体综合征胎儿，或在中期妊娠生化筛查或早孕期联合筛查试验中高风险的胎儿。在 14 周之前和 18 至 21 周检测 18 三体的超声扫描检测率分别为 92.7%和 100%。在≤14 周和 18 至 21 周的异常扫描中，分别有 80%和 87%的胎儿检测到两个或更多超声异常。48 名妇女通过人绒毛膜促性腺激素（hCG）和甲胎蛋白（AFP）的中期妊娠生化筛查筛查出 18 三体综合征阳性，仅有 1 例为真阳性（阳性预测值=1/48 或 2%）。11 名妇女通过 11 至 13+6 周的颈项透明层扫描和母血清妊娠相关血浆蛋白 A（PAPP-A）和 hCG 的早孕期联合筛查筛查出 18 三体综合征阳性，其中 3 例为真阳性（阳性预测值=3/11 或 27%）。所有 4 例筛查阳性的病例均有超声异常。
超声扫描对胎儿畸形是检测 18 三体综合征最有效的筛查试验。在没有超声胎儿异常的情况下，对 18 三体综合征生化筛查或早孕期联合筛查阳性的妇女采取保守管理策略是合理的。可以避免不必要的有创检查。
