OBJECTIVE This study aimed to investigate the relationship between maternal serum pregnancy-associated plasma protein-A (PAPP-A) in the first trimester of pregnancy and the development of preeclampsia (PE), early PE, small-for-gestational age (SGA) fetus and preterm delivery (PD). METHOD This is a retrospective study of 12,355 pregnant women that delivered between 2008 and 2011. We define the first, third and fifth percentiles of maternal serum PAPP-A multiples of the median (MoM). The primary outcome measures were the occurrence of PE, early PE (PE requiring delivery before 34 weeks), SGA fetus (birth weight < 5th centile) and PD. The Mann-Whitney U-test and chi-squared test were used to analyze continuous and dichotomous variables, respectively. RESULTS Maternal serum PAPP-A was significantly lower in women with PE, early PE, SGA fetus and PD (0.91, 0.74, 0.80 and 0.84 MoM, respectively) than in the study population (0.99 MoM) (p < 0.05). The lower the MoM percentile of PAPP-A, the higher are the odds ratio (OR) to develop PE, early PE, SGA fetus and PD. CONCLUSIONS Maternal serum PAPP-A levels are lower in women who develop preeclampsia, those with SGA fetus and those who deliver preterm. However, on its own, maternal serum PAPP-A performs poorly (OR for PE between 1.76 and 2.41 with the lower percentile of PAPP-A) as a screening test for these conditions.