The aim of this study was to investigate whether maternal serum levels of angiopoietin-2 (Ang-2) and pregnancy-associated plasma protein A (PAPP-A) are associated with subsequent intrauterine growth restriction (IUGR). Ang-2 was measured in 29 nonpregnant and 44 pregnant women at 10-13 weeks of gestation. The median concentration of Ang-2 was 26.61 ng/ml in normal pregnant women compared with 1.71 ng/ml in nonpregnant controls (P < 0.01). Women who subsequently developed severe IUGR had lower levels of Ang-2 compared with normal pregnant controls (P < 0.01). PAPP-A levels were similar in all pregnant groups. These findings suggest that Ang-2 should be evaluated for its ability to predict pregnancies that later are affected by IUGR.