Clinical Use of Combined First-Trimester Screening Test for Aneuploidy in A Low-Income Setting: Retrospective Study

Although combined first trimester screening is effective at detecting fetal chromosomal anomalies which are trisomy 21, 18 and 13, there is scarce data on its practice and practice in low-income countries. This study presents data on clinical use of combined first trimester prenatal screening tests among pregnant women in a Sub-Saharan setting.

This retrospective study was conducted over 7 years between July 2016 and June 2023 at St. Paul's Hospital Millennium Medical College (Ethiopia). Risk assessment was done with Snibe 2000 software using maternal age, nuchal translucency, PAPP-A, β-hCG and other maternal characteristics. Statistical analysis was done using SPSS version 22. Fishers exact and Man Whitney U test were done as appropriate, and P-value less than 0.05 was used to present significance of the results.

A total of 141 patients were included in the final analysis. Overall high-risk cases for aneuploidy based on the combined test was 24.8%. Screening positive for aneuploidy had an association with increased nuchal translucency [median (IQR) = 2.1 (1.7, 2.5) for screening negative vs 2.9 (2.4, 2.9) for screening positive test, p-value = 0.021] and low PAPP-A values ≤ 0.05 MoM (1 (5%) for negative and 5 (56%) for positive, p-value = 0.005).

The prevalence of screening positive for high-risk aneuploidy in this study was higher than in previous reports which may be due to the fact that the study population is primary high-risk women. Nuchal translucency and low PAPP-A values were associated with screening positive for aneuploidy. Combined first trimester screening is feasible and effective for detecting fetal chromosomal anomalies in low-income settings. Laboratory capacity for performing serum analytes and genetic testing, and availability of nuchal translucency ultrasound services should acted up on for creating a wider access to such vital prenatal genetic screening and testing services.