Sir my sister, 29 years old married for 2 years, regular 30d cycle, follicular study normal, got pregnant after clomiphene induction 2nd cycle, but missed abortion happened after 8 weeks. Now she is trying to get pregnant, took 2 cycle of letrozole and 1 cycle of clomiphene, all failed. Now ssg done and there is back flow of saline, not passing through both tubes. Advised to do laparoscopic tubal cannulation. She is also having a chocolate cyst left ovary. Sir if tubes are blocked then how did the first pregnancy happen?