Systematic Review of First-Trimester Ultrasound Screening for Detection of Fetal Structural Anomalies and Factors That Affect Screening Performance

Abstract

Table 1 -Characteristics of studies reporting on the detection of structural anomalies in low risk and unselected populations using first trimester ultrasound. Notes: (i). In studies where both TA and TV ultrasound were used, the number in parentheses adjacent to the ultrasound modality refers to the percentage of the study population which received this screening test (when available). (ii). In studies where aneuploid fetuses were included, the percentage of the study population confirmed by karyotyping as aneuploid was indicated in parentheses (where available). (iii). The subgroup analysis column identifies the group(s) in which the respective study's data was analyzed. * Highlights studies where TV ultrasound was only performed in situations where visualization with TA ultrasound was deemed suboptimal. **Cardiac exam performed at time of first trimester scan, but cardiac malformations excluded from study analysis. ***For the purposes of this review, only the cohort of known euploid fetuses was included in analysis (as insufficient data was provided on the entire cohort reported in the study). GroupYear N Gestation (weeks) Population Health-Care Setting Aneuploid Included? Index Test Anatomy Checklist Cardiac Exam Done? Subgroup for data Analysis Achiron (62) 1991 800 9-13 Mixed indications: vaginal bleeding, dating and early anomaly screening Unclear Yes TV/TA Basic Yes 2 Hernadi (37) 1997 3991 11-14 Unselected Unclear Yes (0.2%) TV Basic No 1 Bilardo (25) (Low risk) 1998 1543 10-14 Consecutive, Singleton pregnancies, Normal NT (<3.0mm),

Pregestational diabetes in pregnancy: Complications, management, surveillance, and mechanisms of disease—A review

“…The false positive rate was not reported in the majority of the included studies, and so is still a consideration when planning access to early diagnosis. 35 It should also be noted that despite the high levels of detection reported from these published studies, many in tertiary centres, population-based detection of cardiac anomalies at mid trimester in the general population is still around 70%. 36…”

Development of a training program for the ultrasound screening of placenta accreta spectrum disorders

“…The majority of routine anomaly scanning around the world is still performed in the second trimester, at 18–22 weeks. Over the last two decades, an increasing number of fetal abnormalities have been detected at 11–14 weeks of gestation with rates of detection of first‐ trimester fetal anomalies ranging from 32% in low‐risk groups to more than 60% in high‐risk groups . Of the factors examined for their impact on the rate of detection, the use of standardized anatomical protocols has been shown to significantly improve the sensitivity of ultrasound examination for the detection of fetal anomalies in all subgroups …”

A new comprehensive paradigm for prenatal diagnosis: seeing the forest through the trees

“…Thus, we can expect to detect several major structural anomalies (such as exencephaly, alobar holoprosencephaly, ectopia cordis, omphalocele, gastroschisis, megacystis, thanatophoric dysplasia and body‐stalk anomaly) even at the first‐trimester scan. In fact, nowadays, in experienced centers, one should expect up to half of all major structural defects to be detected at this early anatomic scan.…”