What Causes Missed Periods After Two Consequent Abortions?

hello doctor my age 35, husband 42 married 2 years back. Abortioned 8 months back 2 times with a gap of 4 months. Now I am not getting periods last 2 months. If I go to pregnancy test, the result come negative. My doctor said due to harmones deficiency and she suggested to get complete blood and thyroid test. The test came t3 is 1.0; t4 is =7.20; tsh is 2.40. So kindly advise us to follow the precautions and reason of non-periods is it cause of thyroid or any kindly let me know your valluable suggestions.