This is what my last several posts have been about. I had my Mirena removed in November...had 2 regular periods. Then...month 3...nothing. I finally started today...a whole month late. I had negative tests all along, but still worried that I could be pregnant. I just don't think my body is up to it yet after getting off this horrible Mirena.
The only advice I can give if you are wanting to become pregnant with an irregular period is to pay attention to your ovulation signs...thicker mucus... a high soft cervix. Get your hormone levels checked.