Table 1.
Glossary of key terms.
Table 2.
Outcomes of interest.
Fig 1.
Diagram to show the flow of screening stages and number of papers at each stage of the systematic review. It includes details from both the initial search up to 10th May 2022, and the updated search on 29th March 2023.
Fig 2.
Autonomous regions that have implemented NIPT into antenatal screening guidelines for Down’s syndrome.
Presenting data from included studies in part A. This includes data from Gadsboll et al., [16] describing national NIPT implementation following survey responses by clinical experts (labelled in figure). Map created using Mapchart.net under a CC BY 4.0 license, with permission from Minas Giannekas, original copyright [2023]. NIPT = non-invasive prenatal testing.
Table 3.
The implementation methods of NIPT reported in the included studies of part A, when NIPT has been implemented as part of a national screening programme for Down’s syndrome.
Fig 3.
Flow diagram for each pathway of NIPT implementation described in our included studies.
NIPT has been implemented as both a first or second line screen, in some cases the option of both is offered to those undergoing screening for Down’s syndrome. NIPT = non-invasive prenatal testing, CVS = chorionic villus sampling, NT = nuchal translucency.
Table 4.
Uptake of NIPT for DS screening among eligible pregnancies in a population.
Fig 4.
Forest plots for meta-analyses of proportions of IPDs chosen by higher chance pregnancies after biochemical screening for DS.
A) pre-NIPT implementation B) post-NIPT implementation. C) Odds ratio meta-analysis, comparing the pre and post NIPT implementation time periods for the odds of having an IPD procedure in higher chance women.
Fig 5.
Forest plot of the pooled estimate for proportion of higher chance pregnancies (resulting from biochemical screening) that went on to have an invasive prenatal diagnosis (IPD) after NIPT was implemented as a second line screen.
Fig 6.
A) Forest plot of pooled proportion of women with a high chance NIPT result that opt for an IPD procedure (NIPT available as a first line screening test); B) Forest plot of pooled proportion women with high chance NIPT result that opt for an IPD (NIPT available as a second line screening test).
Table 5.
Subgroup and meta-regression analyses results.
Fig 7.
Forest plot of the proportion of terminations of pregnancy following a high chance NIPT result for DS, in the post-NIPT period.
Fig 8.
Forest plot of meta-analysis of proportion for live births of babies with Down’s syndrome born after a high chance NIPT result.