I got my Mirena taken on the first of march, I ovulated between the 21st and the 25th, and did the BD on the 22nd and flubs out I was pregnant on April 4th. I love the <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> because I could calculate my ovulation and I could put in symptoms and notes and I really helped me. Thank you Glow!!