... told me it was effective right away and that I could DTD as soon as I felt up to it. I am EBF, so I have not had my first postpartum period. DH and I DTD yesterday, 4 days after Mirena placement. I am now reading that Mirena is only effective immediately if placed within the first seven days of the menstrual cycle and that backup protection should be used for seven days if placed at any other time during the cycle. Since I haven't had my first postpartum period I'm confused about this. Should we have used backup protection in this case? Anyone have any experience with this or any advice?