<prompt> Which of these is the most commom cause of Primary Amenorrhea ?Constitutional idiopathicMayers rokitansky kustner hauser syndrome MRKHGonadal dysgenesisAndrogen Insenstivity syndrome  <response>: Primary Amenorrhea- In absence of secondary sexual characters, no menses till the age of 13 years - In presence of secondary sexual characters, no menses till the age of 15years Causes: Ovarian dysgenesis , also termed gonadal dysgenesis in women is most common cause. In this, turners syndrome is the commonest variety of gonadal dysgenesis. Mullerian agenesis, though the 2nd most common cause, its also the most common anatomical cause. Constitutional delay is the 3rd most common cause. 