Background Controversies about the performance of conventional prenatal screening using maternal serum and ultrasound markers (PSMSUM) in detecting Down syndrome (DS) have been raised as a result of a recently available noninvasive prenatal test based on cell-free fetal DNA sequencing.Objectives To evaluate the screening performance of PSMSUM in detecting DS in Chinese women.Search strategy An exhaustive literature search of MEDLINE, Embase, the Cochrane Library, ISI Web of Science and China BioMedical Disc.Selection criteria Primary studies, published from January 2004 to November 2014, which examined the screening accuracy of PSMSUM in pregnant Chinese women, compared with a reference standard, either chromosomal verification or inspection of the newborn.Data collection and analysis Data were extracted as screening positive/negative results for Down and non-Down syndrome pregnancies, allowing estimation of sensitivities and specificities. Risks of bias within and across studies were assessed. Screening accuracy measures were pooled using a bivariate random effects regression model.Main results Seventy-eight studies, involving six categories of PSMSUM, were included. Second-trimester double serum [pooled sensitivity (SEN) = 0.80, pooled specificity (SPE) = 0.95] and triple-serum (pooled SEN = 0.79, pooled SPE = 0.96) screening were the predominant PSMSUM methods. The screening performances of these methods achieved the national standard but varied enormously across studies. First-trimester combined screening (pooled SEN = 0.92, pooled SPE = 0.93) and secondtrimester quadruple serum screening (median SEN = 0.86, median SPE = 0.96) performed better, but were rarely used.Author's conclusions Second-trimester maternal serum screening has the potential to achieve satisfactory screening performance in middle-and low-income countries. The reported enormous range in screening performance of second-trimester PSMSUM calls for urgent implementation of methods for performance optimization.Keywords Down syndrome, prenatal screening, systematic review, trisomy 21.

No abstract

No abstract