Very elevated hCGβ (≥10 multiple of the median) in maternal marker screening for Down syndrome: Frequency, etiologies, outcomes, and guidelines.

Aim: This aim of this study was to detail maternal and fetal anomalies observed on a national scale in a large French cohort of patients presenting high hCG values (≥10 multiple of the median [MoM]) at Down syndrome screening in order to define clear and optimal guidelines.

Methods: This is a retrospective multicenter study based on a French annual database of all trisomy 21 screenings. Our study targeted and studied cases with hCG or hCGβ values ≥10 MoM. Complementary exams and outcomes were analyzed.

Results: The calculated frequency was 0.05% for hCGβ ≥10 MoM in unselected patients. For this series of 289 cases, a complication of the pregnancy or a poor outcome was observed in 145 cases (51%) as follows: 96 (66%) cases of fetal disease, 23 (16%) of maternal disease, 5 (3.5%) of placental anomalies and 21 (14.5%) of systemic disease concerning mother, fetus and placenta.

Conclusion: This study establishes the frequency of hCG or hCGβ values ≥10 MoM, presents a flow chart that optimizes follow-up, and gives clear information for patients presenting with such abnormal values at trisomy 21 screening.