I had one post delivery though as had post parting haemorrhage. I believe my iron was low during the third trimester but my dr wasn't too concerned. It took about 5hrs to go through. It didn't hurt at all. My levels jumped very quickly but then dwindled down again after a few weeks. I did lose 1/3 of my blood though so it's a different situation than you. If you have any other questions about it just ask.