The Influence of the Introduction of Fetal Anomaly Scans on Pregnancy Terminations in Cases of Upper Limb Anomalies: A Retrospective Cohort Study From 2000 to 2023

Abstract

Objective: To examine the association between the introduction of the fetal anomaly scans in the Netherlands and termination of pregnancy (TOP) in cases of prenatally detected upper limb anomalies.

Methods: We conducted a retrospective study among prenatally detected upper limb anomalies between 2000 and 2023. Anomalies were categorized as reduction defects, syndactyly, or polydactyly, and classified as isolated or non-isolated. We analyzed TOP rates across three periods (2000-2006, 2007-August 2021, September 2021-2023), including an interrupted time series (ITS) analysis to assess the impact of introducing second- and first-trimester anomaly scans (STAS, FTAS).

Results: We included 300 pregnancies, of which 133 (44.3%) were isolated. Overall TOP rates did not differ significantly between periods, except for isolated reduction defects, where a significant increase was observed (p = 0.032). TOP rates over time did not increase for syndactyly and polydactyly. Median gestational age at diagnosis decreased across the three periods: from 20.4 to 19.4 weeks and then to 14.9 weeks. Similarly, the timing of termination of pregnancy decreased from 20.5 to 16.8 weeks and then to 15.0 weeks.

Conclusion: Earlier prenatal detection followed the introduction of STAS and FTAS. Despite this shift in timing, no consistent changes in termination rates were observed across the study periods. While overall TOP rates remained stable, a trend towards higher termination rates was observed for isolated reduction defects.

Keywords: fetal anomaly scan; polydactyly; pregnancy outcome; prenatal; reduction defect; syndactyly; termination of pregnancy; upper limb anomaly.

FIGURE 1

Termination of pregnancy (TOP) rates for fetuses with reduction defects, syndactyly, and polydactyly, stratified by whether the anomaly was sonographically isolated or non‐isolated, and further subdivided by genetic test outcome (normal, abnormal, or unknown). Proportions are shown as n/N (%), and visualized below each group.

FIGURE 2

Three year average termination of pregnancy (TOP) rates for reduction defects, syndactyly, and polydactyly, separated by whether the anomaly was isolated or non‐isolated. Detailed information on these are included in Supporting Information S2: Additional File 2.