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. Key points What's already known about this topic? High hCG or hCGβ values have been previously reported to be associated with poor prognosis, when over 2.5 multiple of the median (MoM). What does this study add? This study specifies maternal and fetal anomalies observed in patients presenting high hCG values (≥10 MoM) at Down syndrome screening in order to define clear and optimal guidelines. We calculate the frequency of this abnormal value of hCGβ, detail the outcomes, present a flow chart that optimizes follow‐up and provide clear information for patients.