I had the same thing happen to me when I was 8.5 weeks pregnant. I was scared so I called my doctor gave me an ultrasound said there was a heart beat, so I was relieved. But I was still worried because I had bleeding at 11.5wks, 13wks, 16wks, 18wks. My doctor gave me another ultrasound and baby was fine, I still wasnt convinced. When I was 20 weeks along I ended up changing doctors for a number of reasons and my new doctor gave me a vaginal pelvic exam(becuase my other doctor never had), he check my cervix and noticed that when he touched it bled. He said that the bleeding was coming from my cervix and not from inside my uterus.It was such a relief for me. He said that when your pregnant your cervix has increased blood flow and the blood vessel become engorged which can cause bleeding esp after sex, over-exhurtion and maybe bowl movements or urinating. And also I still have bleeding almost weekly and Im almost 26 weeks. I hope my answer helps and tell your wife to make sure the doctor checks her cervix.