Yes, it is possible that taking Orilissa can result in a decrease or absence of menstrual periods. This effect is mentioned by the manufacturer as a possible side effect of the medication. It is important to note that this change in menstrual cycle does not necessarily indicate a decrease in fertility. While periods may become less reliable as an indicator of pregnancy, the majority of women have reported resuming their normal menstrual cycle within a month after stopping treatment with Orilissa.