I am a rare case. I got pregnant on my period, long story short, my husband and I were TTC for 8 months, nothing was happening, till one drunken night I was on my period and we had sex (I was always against period sex) 3 weeks later I got my BFP, my doctor was a tad shocked wheb explaining it after my first ultrasound. It explains why I wasn't getting pregnant, I was only ovulating on my period.