We investigated the association of first trimester low maternal serum pregnancy-associated plasma protein-A (PAPP-A) levels with small-for-gestational age (SGA) newborns and stillbirths (SBs) in a retrospective national population-based register study. The study group comprised 921 women with the lowest 5% PAPP-A levels (< or =0.3 MoM) and the control group comprising 18,615 women with PAPP-A levels >0.3 MoM. In the study group there were 35 (3.8%) and in the control group 213 SGA newborns (1.1%), respectively (OR, 3.41; 95% CI, 2.37-4.91). There were 9 (1.0%) and 51 (0.3%) cases of SBs in the study and control groups, respectively (p < 0.002; OR, 3.59; 95% CI, 1.76-7.32). Low PAPP-A is a risk factor for SGA and SB.