Women with polycystic ovary syndrome (PCOS) tend to have elevated anti-Müllerian hormone (AMH) levels, which appear to correlate with disease severity and pregnancy outcomes. This was a retrospective observational study designed to assess the relationship between circulating AMH levels and in vitro fertilization (IVF) outcomes. The study involved 150 women with PCOS who underwent IVF treatments. The women’s IVF cycles were allocated into three subgroups according to AMH levels: ‘low’ (AMH < 3.7 ng/mL; n = 49), ‘middle’ (AMH 3.7–7.4 ng/mL; n = 94), and ‘high’ (AMH > 7.4 ng/mL; n = 56). All pregnancy-related outcomes (positive beta human chorionic gonadotropin (βHCG), clinical pregnancy rate, live birth rate, and cumulative live birth rate) were greater in women’s IVF cycles with ‘low’ AMH when compared to those with ‘middle’ or ‘high’ AMH (p < 0.05). AMH levels below 3.7 ng/mL were found to be associated with lower oocyte immaturity rate and better pregnancy outcomes, although baseline AMH was not shown to have any significant predictive power for live birth and cumulative live birth in the multivariable logistic regression analysis after adjusting for possible confounders nor in the ROC analyses. In summary, the current study lays the groundwork to validate high AMH levels as a poor prognostic factor for pregnancy outcomes after IVF in women with PCOS.