excuse my typos... My keyboard is on its way out
Oh and another thing.. If her periods are irregular all the more reason to check out what I did to get pregnant. I was charting my body temp each morning at the same time to fin when my spike in tempertur occurrs. I did this for two months and in the second month I used the first months example before the spike hit to try and concieve and used, Other things to help my chances. Your friend may take alittle longer than two monks to figure her cycle out but it does help to have yr periods regular first. But she can still do the charting just to seen how it works and the amount of difference her periods are from each month. She can go onto the Internet and read up on body basal temperture charting for pregnancy.
I'd suggest shs seek advice from a doctor like an OB so they can dig deep and find out. She may have a hormone imbalace like adgal said. Pcos is one reason and thyroid could be another but get it checked. A normal healthy couple 'may' indeed take over a year to concieve but there are many who concieve first try like myself. Just know there is no set time of when one concieves... Up to the body to decide. On my profile here I have some techniques I usd to help me get pregnant in my journal. Once her periods return she should check my stuff out. Good luck
It is not possible for us to tell you why her periods aren't regualar..it could be a hormonal imbalance or many other things. She needs to see a Dr. Good luck
If she has only come off of bc in the last 6 months her body may still be adjusting to coming off of bc.
How long has she been ttc? it takes a normal healthy couple 1-2 years to conceive.
I would suggest she speak to a doctor if her periods are still irregular after 6 months best of luck to them