Last ob appt bub was breech n measured 1 week ahead on weight on us. this week at 32 wks, she measured 4 days behind but is now head down. why is that

Sounds ok: Most breech babies will spontaneously convert to head down as you approach your due date. This is normal and expected. On a 32 week sonogram the margin or error is +/- 3 weeks so your baby measures within the margin of error on this sonogram as well as the last one. More specific details will need to be addressed by your doctor who can look at the sonogram report itself.