Investigating the Relationship between Serum Levels of PAPP-A and Free β-hCG in the First Trimester of Pregnancy with Placental Thickness and Percentile of Fetal Weight in Third Trimester Ultrasound. EJMED [Internet]. 2024 May 31 [cited 2025 Oct. 10];6(3):10-5. Available from: https://www.ej-med.org/index.php/ejmed/article/view/2107