IntroductionThe aim of the present study was to evaluate the effects of different polycystic ovary syndrome (PCOS) phenotypes using first-trimester placental three-dimensional power Doppler indices and placental volume. MethodsIn this prospective case-control study, 170 pregnant women who met the inclusion criteria were divided into five groups according to PCOS phenotype: non-PCOS control (n = 34), PCOS phenotype A (n = 34), PCOS phenotype B (n = 34), PCOS phenotype C (n = 34), and PCOS phenotype D (n = 34). The primary outcomes determined in the present study were the differences in placental volume and placental flow index (FI), vascularization flow index (VFI), vascularization index (VI), and uterine artery pulsatility index (PI) betweenthe PCOS groups and control group. ResultsThe mean placental volume and VI were significantly decreased in the phenotype A, B, and C groups compared to the control group and PCOS phenotype D group. The mean FI and VFI were significantly decreased in the phenotype A and B groups compared to the control group and PCOS phenotype C and D groups. The mean testosterone, dehydroepiandrostenedione, sex-hormone binding globulin, free androgen index, and insulin resistance levels were significantly increased in the phenotype A, B, and C groups compared to the control group and PCOS phenotype D group. DiscusionThe results indicated that placental volume and placental vascular Doppler indices in the first trimester were more adversely affected in the PCOS A and B phenotypes than other PCOS phenotypes.