Ashe R G, Dornan J C, Patterson C C, Thompson W
Dept of Obstetrics and Gynaecology, Royal Victoria Hospital.
Ir Med J. 1996 Sep-Oct;89(5):180-2.
The objective of this study was to evaluate routine obstetric ultrasound in detecting fetal structural anomalies and the impact of changing clinical practice on success rates. A retrospective study of routine ultrasound in a population of 6,869 pregnancies was performed during 1985-86 (phase 1) to establish efficacy of ultrasound in the detection of fetal anomalies. Changes in ultrasound practice comprised timing, personnel and technique of fetal examination. After alterations in practice, a prospective study of 6,969 pregnancies during 1987-89 (phase 2) was performed. All abnormal fetuses (cases) were assessed in both studies. Random samples of normal infants (controls) were chosen from both populations to establish specificity. In 83 cases in phase 1,116 anomalies were diagnosed postnatally of which 11 were suspected by routine prenatal ultrasound at < 24 weeks (sensitivity 9%, 95% C.I. 4-15). In 72 cases in phase 2, 89 anomalies were identified postnatally of which 27 were suspected by routine prenatal ultrasound at < 24 weeks (sensitivity 30%, 95% C.I. 21-41). The change in sensitivity was statistically significant (p = 0.0003). Of the 382 control infants randomly selected in phase 1, false abnormal scans were not identified (specificity 100%, 95% C.I. 99-100). Of the 367 control infants in phase 2, 12 false abnormal scans were identified (specificity 96.7%, 95% C.I. 95-99). The decrease in specificity was statistically significant (p = 0.0013). The detection of urorenal and to a lesser degree central nervous system anomalies showed most improvement between the two phases. The alterations to routine ultrasound practice in timing, personnel and technique have significantly improved the detection of all fetal structural anomalies but at the cost of a small but significant loss of specificity.
本研究的目的是评估常规产科超声在检测胎儿结构异常方面的作用，以及临床实践的改变对成功率的影响。1985 - 1986年（第一阶段）对6869例妊娠进行了常规超声回顾性研究，以确定超声检测胎儿异常的有效性。超声实践的改变包括胎儿检查的时间、人员和技术。在实践改变后，1987 - 1989年（第二阶段）对6969例妊娠进行了前瞻性研究。在两项研究中均对所有异常胎儿（病例）进行了评估。从两个群体中选取正常婴儿的随机样本（对照）以确定特异性。在第一阶段的83例病例中，产后诊断出116例异常，其中11例在孕24周前被常规产前超声怀疑（敏感性9%，95%可信区间4 - 15）。在第二阶段的72例病例中，产后发现89例异常，其中27例在孕24周前被常规产前超声怀疑（敏感性30%，95%可信区间21 - 41）。敏感性的变化具有统计学意义（p = 0.0003）。在第一阶段随机选取的382例对照婴儿中，未发现假阳性扫描（特异性100%，95%可信区间99 - 100）。在第二阶段的367例对照婴儿中，发现12例假阳性扫描（特异性96.7%，95%可信区间95 - 99）。特异性的降低具有统计学意义（p = 0.0013）。两个阶段之间，泌尿生殖系统异常以及程度稍轻的中枢神经系统异常的检测改善最为明显。常规超声实践在时间、人员和技术方面的改变显著提高了所有胎儿结构异常的检测率，但代价是特异性有小幅但显著的降低。
