I'm 29 y/o female. I had my thyroid completely removed due to nodules, 11 years ago. At the time of the removal, I had been on birth control pills. I remained on them for 10 years. I took Synthroid, and never had a problem. I felt great! I got off the BC pills 2 years ago, and all of a sudden, I am unable to tolerate my synthroid. Especially after ovulation! I become extremely stimulated by it, and can only take 1/4 of the pill at a time. It seems to get better when I approach ovulation, when my hormone levels are the highest. My ability to tolerate my synthroid seems to follow my menstural cycle. And I ovulate every OTHER month. This causes me to constantly go from hypo to normal to hypo to normal. As I approach ovulation, I am able to take my entire correct dose of synthroid, and end up with a good TSH. However, then I ovulate and all of a sudden can't tolerate my thyroid pill for about 3-4 weeks after! So, this causes my TSH to go high. I've had my hormones tested and my estrogen and progesterone levels are always low. Do you think this is the reason why I'm unable to tolerate my synthroid- because of low hormone levels?? I have heard that having low estrogen causes one to be more sensitive to thyroid hormone. Anybody have any experience with this??