Abstract:BACKGROUND: The purpose of the study was to examine the prevalence of spontaneous abortion in patients with polycystic ovary syndrome (PCOS) compared with patients with tubal factor infertility. We also wanted to test the hypothesis that the miscarriage risk might not increase with age in PCOS, as PCOS patients are thought to have a greater than average ovarian reserve.METHODS: Retrospective study of women undergoing assisted reproductive treatment at a tertiary university hospital in Oslo. We retrieved clinical records of all women with PCOS (n = 541) or tubal factor infertility (n = 1129) who conceived after assisted reproduction treatment in 1996-2010. Pregnancy outcome was divided according to fetal viability at 6 weeks’ and 12 weeks’ gestation, and was tabulated for age. Chi-squared test for linear trend was used. Prevalence of live birth and spontaneous abortion was also calculated according to diagnosis.RESULTS: Prevalence of live birth was 68.8 % in the PCOS group and 69.3 % in the tubal factor group. Prevalence of spontaneous abortion between gestational weeks 6 and 12 was 10.8 % in the PCOS group and 9.6 % in the tubal factor group. The prevalence of spontaneous abortion during 6-12 weeks’ gestation increased significantly with age among women with tubal factor infertility (P = 0.01), but not among women with PCOS (n = 0.55).CONCLUSIONS: The prevalence of spontaneous abortion between gestational weeks 6 and 12 and prevalence of live birth were similar between groups. The prevalence of spontaneous abortion does not increase significantly with age up to 40 years in women with PCOS. This could be because of their greater ovarian reserve. Further studies are needed to examine the exact mechanisms for this.