Greetings from health care magic!!! I am Dr Thakker and shall be answering your question.
I very well understand your concerns about subclinical hypothyroidism
and conception. I will try my best to answer your question and guide you through the problem.
Subclinical hypothyroidism is a condition in which the blood TSH
levels are high and T3, T4 levels are normal. This means the body is overstraining the thyroid gland to maintain your thyroid levels in the normal range.
Subclinical hypothyroidism must be treated with thyroid supplementation irrespective of symptoms. Titrate the dose to keep TSH between 2.5 and 4.5. You can begin with a small dose of 25 microgram per day. (some conservative physicians prefer not to supplement and wait till TSH gets really out of range. This approach is not advisable especially since you wish to conceive.)
Hypothryroidism does affect conception, retention of pregnancy
and the brain develoment. This is very important especially in the first 8 weeks when the brain development of the fetus occurs. If not corrected it can affect the brain development leading to cretinism
Hence I would sincerely advice you to start thyroid supplementation in low dose and repeat tsh after 6 weeks.
I hope this helps you out. If you have any more questions, please do not hesitate to write back to me.