Objective: To investigate if first trimester lipids, sonographic parameters and serum markers are related to small- and large-for-gestational age (SGA, LGA) infants. Methods: This study was conducted at Baskent University Adana Research Center between December 2009 and July 2011 and enrolled 433 women. Blood samples were drawn to measure fasting blood glucose, serum triglycerides, cholesterol, very low-density lipoprotein, low-density lipoprotein, high-density lipoprotein, fβ-hCG and pregnancy associated protein-A (PAPP-A) at the first trimester. Crown rump length and nuchal translucency were measured as suggested by the fetal medicine foundation. Results: LGA group was significantly taller ( p = 0.016) and SGA group had significantly greater BMI (0.025). SGA fetuses were born at a significantly earlier gestational age ( p = 0.001). Univariate analysis revealed that LGA group had significantly lower cholesterol ( p = 0.038) and LDL levels ( p = 0.041). PAPP-A was significantly lower in SGA Group compared with LGA Group (0.027). After controlling for age, parity, height, pre-pregnant BMI, weight gain during pregnancy and fasting blood sugar, none of the lipids, serum markers or sonographic parameters was related to LGA. PAPP-A was the only parameter significantly associated with SGA after multivariate analysis ( p = 0.008). Conclusion: PAPP-A was significantly associated with SGA after controlling for confounders. [ABSTRACT FROM AUTHOR]