Macroscopic and microscopic findings of the placenta in women with polycystic ovary syndrome

STUDY QUESTION: Do patients with polycystic ovary syndrome (PCOS) have macroscopic and/or microscopic placental alterations? SUMMARY ANSWER: The placental structure in patients with PCOS, even in those with uncomplicated pregnancy, is altered. WHAT IS KNOWN ALREADY: The spectrum of pregnancy complications seems to have a common denominator: a defective trophoblast invasion and placentation. In women with PCOS, alterations in endovascular trophoblast invasion related to insulin resistance and hyperandrogenism have been observed. STUDY DESIGN, SIZE, DURATION: For this prospective case-control study, 30 pregnant patients with PCOS (cases) and 60 healthy pregnant women without PCOS features (controls) were enrolled and studied until delivery. Clinical, biochemical, ultrasonographic and obstetric data were recorded. The baseline clinical and biochemical data for screening for PCOS and for inclusion/exclusion were obtained before the seventh week of gestation. At delivery, placentas were collected and detailed macroscopic and microscopic analyses were performed. PARTICIPANTS, SETTING, METHODS: Cases and controls were matched for age and BMI (all <30 kg/m(2)). The matching procedure was one-to-two. Only subjects with spontaneous conception and uncomplicated pregnancies were included in the final analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Placental weight (P = 0.04), thickness (P = 0.02), density (P = 0.02) and volume (P = 0.01) were significantly inferior in women with, compared with those without PCOS. The placentas from patients with PCOS more frequently had an irregular shape (P = 0.03) and a higher cord coiling index (P = 0.02). Differences between cases and controls also concerned the extent of villous (P = 0.04) and intervillous (P = 0.01) spaces, the extent of fibrosis (P = 0.03), endovascular trophoblast (depth, extension and morphometry) (P < 0.05) and mitotic activity (P = 0.01). The percentage of patients with lesions [22/30 (73.3%) versus 25/60 (41.7%), respectively; P = 0.01] and the mean number of placental lesions (3.5 ± 2.1 versus 1.4 ± 1.1, respectively; P = 0.02) were higher in the PCOS than the control group. The odds ratio for placental alterations, adjusted for weight gain, was 2.8 (95% confidence interval 1.3-9.9). LIMITATIONS, REASONS FOR CAUTION: The main limitation of the study was the selection of a specific PCOS sample, which is probably not representative of the PCOS phenotype as a whole. In fact, we excluded patients with PCOS who were obese and who achieved a pregnancy following the use of ovulation inductors or assisted reproduction techniques. WIDER IMPLICATIONS OF THE FINDINGS: The present study is the first to demonstrate that the morphology and microscopic structure of placenta in patients with PCOS with an uncomplicated pregnancy are altered. Further studies are needed to assess a correlation of these changes with the increased risk of obstetric complications observed in some pregnancies of women with PCOS. STUDY FUNDING/COMPETING INTEREST(S): The authors declare no conflict of interest and no financial support for the research. TRIAL REGISTRATION NUMBER: N/A.