The time I came off the pill (was only on it momentarily) it stretched my cycle. I just never had a period afterwards but I couldn't have ov ed 2wks after, it must have been a bit later, as then I didn't get a bfp for ages. In those days they went by your lmp for a baby due date, not the scan, so of course he was 10 days overdue in theory. But spontaneous onset so I've always been a bit dubious. It could just be that surge will be a bit later.