In 2003, the angiotensinogen (AGT) gene was found to be associated with infants small for gestational age (SGA). The present study of 107 pregnancies affected by SGA infants and 101 normal pregnancies was designed to further investigate this association. Maternal or fetal AGT genotype or haplotype frequencies did not differ between SGA and normal pregnancies (P > 0.35). Quantitative trait analysis of mothers with normal pregnancies demonstrated an association between AGT haplotype and blood pressure and body mass index at antenatal booking (P = 0.04), suggesting that AGT may play a role in the complex relationship between body mass and blood pressure in healthy pregnant women.