My periods are irregular. Could this be a reason for my infertility

As long as the periods are regular, this means ovulation is occurring. Some normal women have menstrual cycle lengths of as long as 40 days. Of course, since they have fewer cycles every year, the number of times they are “fertile” in a year is decreased. Also, they need to monitor their fertile period more closely, since this is delayed (as compared to women with a 30 day cycle).