I have been diagnosed with blighted ovum, @7 weeks, 2days. After d & c, how many cycles should we wait again before trying? Affects future pregnancies?

Wait 1 normal period. Sorry to hear of your loss. After a D&C your pregnancy hormone (HCG) will fall down to zero in a few weeks, with some bleeding at that time. Wait 1 more cycle after this before trying again - after your next 'normal period'. There may be a higher chance of another miscarriage in the 1st month, so use condoms. 1 miscarriage is common, if you have 2 or more see a rei specialist to get checked out.