Objective: To evaluate the effect of maternal polycystic ovary (PCO) morphology on maternal serum free beta-human chorionic gonadotropin (β-hCG), pregnancy associated plasma protein A (PAPP-A), and nuchal translucency (NT) thickness in the first-trimester. Material and Methods: A total of 92 pregnant women in the first-trimester were included in the study. Of them, 57 had PCO morphology, and 35 women constituted the control group, with apparently normal ovaries. Maternal serum free β-hCG, PAPP-A, and NT thickness were measured and compared in all patients. Results: The multiples of median (MoM) levels of serum free β-hCG were significantly higher in the PCO morphology group compared to the normal ovary group (p = 0.024). However, the MoM levels of PAPP-A were similar in both groups (p = 0.947). No difference was found between the groups in terms of fasting glucose levels and NT measurements (p = 0.976 and 0.565, respectively). Conclusion: In pregnancies with maternal PCO morphology, the presence of higher maternal serum free β-hCG levels may require correction in the calculation of risks related to first-trimester screening for chromosomal abnormalities. Larger studies are needed to confirm our preliminary data.