Mine weren't extremely short (typically 12 days) but I had lots of heavy spotting prior to my period which really made my lp more like 8-9 days. I took 50 mg of B6 daily to help with the spotting (and it did). I did have one early m/c that I think could possibly have been related to short luteal phase but this one has been healthy so far. Good luck!
Re: short lp
What do you consider short?
Mine was 10 days and I got a BFP on 9DPO. Baby clearly "stuck."
Good luck.