Introduction: Preeclampsia occurs between 2% and 7% of pregnancies. Previous studies have suggested an association between altered levels of PAPP-A and the free β-hCG with the development of preeclampsia (PE) or infant’s small for gestational age (LBW)Methodology: The design of the study is diagnostic tests. Serum measurements of PAPP-A and free β-hCG were performed between 11-136/7 weeks and 6 days, for a period of 2 years. Results: The cohort included 399 patients; the incidence of PE was 2. 26% and 14. 54% was LBW. The 10th percentile cutoff for MoM PAPP-A was 0. 368293 and for MoM β-hCG: 0. 412268; the specificity for PE was 90, 5% and for LBW 90%. The MoM free β-hCG, the maternal age and weight behave as risk factors, while higher MoM values of PAPP-A and higher parity as protection factors. For severe SGA, maternal age and parity behave as risk factors, whereas an average increase of MoM values of PAPP-A and free β-hCG, as protective factors in the development of severe SGA. Conclusions: There is a significant relationship between the altered levels of PAPP-A and free β-hCG, measured at week 11 to 136/7 with the incidence of preeclampsia and low birth weight in chromosomally normal fetuses, showing significantly lower levels with increasing severity of disease.
