Participants
This study is a subgroup analysis of a multi-center prospective cohort
designed to investigate the cost-effectiveness of various prenatal test
strategies after the introduction of cfDNA screening. The protocol was
published prior to the analysis of this study [8]. In brief, the
prospective cohort study was performed in 12 different secondary and
tertiary health care institutions between June 2016 and October 2018.
Singleton pregnant women who underwent NT ultrasound examinations were
included and counseled regarding fetal aneuploidy screening or
diagnostic test before 24 gestational weeks. The cases with unknown
pregnancy outcomes were excluded in our study.