Association of serum PAPP-A levels in first trimester with small for gestational age and adverse pregnancy outcomes: systematic review and meta-analysis

Objectives To determine association, and predictive ability, of first trimester maternal serum pregnancy associated plasma protein A (PAPP-A) with adverse pregnancy outcomes. Method Searches of Medline, Embase and CINAHL (inception September 2015) for studies including pregnant women with first trimester PAPP-A and assessment of pregnancy outcomes. Study characteristics, quality and results extracted. Meta-analysis of odds ratios (ORs), and likelihood ratios (LRs) and 95% confidence intervals (CI). Results Thirty-two studies including 175 240 pregnancies. PAPP-A <5th centile had a moderate association with: birth weight <10th centile OR 2.08 (95% CI 1.89-2.29), <5th centile OR 2.83 (95% CI 2.52-3.18); pre-eclampsia OR 1.94 (95% CI 1.63-2.30), preterm birth <37 weeks OR 2.09 (95% CI 1.87-2.33), and composite adverse outcome OR 3.31 (95% CI 1.80-5.11). The predictive ability was poor: Birth weight <10th centile LR + ve 1.96 (95% CI 1.58-2.43), LR-ve 0.93 (95% CI 0.89-0.98); birth weight <5th centile LR + ve 2.65 (95% CI 2.35-2.99), LR-ve 0.85 (95% CI 0.74-0.98); PTB <37 weeks LR + ve 1.84 (95% CI 1.41-2.39), LR-ve 0.92 (95% CI 0.87-0.98). Conclusions First trimester low maternal serum PAPP-A is associated with adverse pregnancy outcome, but predictive values are poor. Further work should address PAPP-A as a continuous variable in combination with other prognostic markers as a prediction model. (C) 2016 John Wiley & Sons, Ltd.