I had a MC at 8 wks back in early November. Four weeks later - almost to the day - I had a period. TBH I was surprised at how normal it was.
Now seven weeks have passed and nothing. I'm not TTC and it is extremely unlikely that I could be pregnant.
I was scanned a couple of days after the MC. Apparently my uterus was empty and the lining was as it should be so I don't think the MC was incomplete (besides it looked pretty complete to me as it actually happened).
I guess it takes a while for cycles to settle down after MC, and I'm not desperately worried but I'd be interested to hear from others that this has happened to.