Question: how many weeks are you pregnant during implantation?
Answer: At 4 weeks, the blastocyst has made a 6-day trip from the fallopian tubes to the womb. Here, it begins to burrow or implant into the wall of the uterus. It will take its nutrition from the mother's blood. Meanwhile, the amniotic sac is forming, along with the yolk sac and the placenta.