When's the best cycle time to go for an investigative scan?

[WhenToGo]

I came off the pill about 18 months ago and it took a long time for me to have a period. I used to have irregular periods pre-pill and that seems to be continuing to a degree. After about a year, I had one, followed by another 28 days later, but then nothing for 3 months. I wonder whether I might have PCOS or something like that.

I've been charting BBT for a few months and everything seems to be vaguely predictable in that there is an identifiable pattern (although only based on 2 full months so far, so maybe it's a coincidence). Seems to be 33 days in total with ovulation on day 23.

I'm expecting a letter allowing me to book a pelvic scan imminently (checked the other day and am near top of the waiting list). I was wondering whether anyone had any advice on when in my cycle I should ideally be scanned? It might not be possible, but given that I have an idea from the charting, should I have a target date?

PCO may well be a possibility here; it is a common cause of such irregular cycles.

Have you had any blood tests done as yet?.

I had such scans during weeks 1,2 and 4 during the calendar month as my cycles were pretty much non existent.

If PCO or PCOS is there it can take a skilled sonographer to spot the cystic follicles on the ovaries as these are so small. A polycystic ovary can appear larger though that normal size, a normal size ovary is about the size of a walnut. Also such cystic follicles can disappear - only to be replaced by further such follicles. You will need to have more than one scan done.

Charting can be very hit and miss when irregular periods are an issue as you can end up with a chart somewhat akin to the Rocky Mountains. Also there can be a temp spike in the second half of the cycle when an egg has not been shed so charting itself is not infallible.

Thanks Atilla. Had blood tests just before periods came back (so about 9m ago I think) and they showed nothing.

I know that charting is not necessarily reliable, it just seems like the only thing I can do at the moment. It's not getting me stressed, it's vaguely interesting.