Prefrontal Space Ratio—A Novel Ultrasound Marker in the Second Trimester Screening for Trisomy 21: Systematic Review and Meta-Analysis

Abstract

To determine the value of prefrontal space ratio (PFSR) as a novel soft marker in the second-trimester screening for trisomy 21, PubMed and two other databases were searched electronically for the relevant materials published between January 2000 and December 2015. Four studies were included in the mini meta-analysis. All of the studies were retrospective and of high quality. Overall sample size was 293 trisomy 21 and 609 euploid fetuses. The pooled mean PFSR was 0.322 (95% confidence interval [CI], 0.256-0.388) and 1.205 (95% CI, 0.997-1.413) in trisomy 21 and euploid fetuses, respectively. This ratio was found to be significantly lower in trisomy 21 fetuses compared to euploid ones ( P < .0001). The pooled detection rate was 87.2% at a false-positive rate of 5%. Pooled positive and negative likelihood ratios measured 17.2 and 0.146, respectively. In conclusion, PFSR is an efficient marker that may be investigated in the second-trimester ultrasound screening for trisomy 21.