Objective
To investigate the placental morphology alterations and identify the clinical characteristics of women with polycystic ovary syndrome (PCOS) and their newborns. Pregnant women with PCOS (n = 12) and pregnant women without PCOS (n = 11) were recruited. Then, the placenta, maternal blood and cord blood were collected after delivery. Design: Clinical observational study. Setting: Not applicable. Patient(s): In the present study, pregnant women with PCOS and healthy pregnant women were recruited from the clinic of the Department of Obstetrics and Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, China, between February 2015 and October 2015. Intervention(s): None. Main outcome measure(s): A proteomic analysis was performed on the placenta in women with PCOS and healthy women. Result(s): The maternal testosterone, androstenedione, dehydroepiandrosterone sulfate, free androgen index, cholesterol, apolipoprotein B, and apolipoprotein B/apolipoprotein A-I levels were significantly higher in the PCOS group than in the control group, and the offspring in the PCOS group had higher dehydroepiandrosterone sulfate, high-density lipoprotein, and cholesterol levels, when compared with the control group. The placenta in the PCOS group demonstrated infarction, calcification, and a greater intervillous space, when compared with the control group. A higher level of estrogen receptor-β protein was observed in the placenta of women with PCOS, when compared with women without PCOS. A total of 258 proteins in the placenta were identified to be significantly different, when the PCOS and control groups were compared, and fibronectin 1 exhibited the closest relationship with other differential proteins.