25mcg is such a low dose to be negligible. 50mcg is usually a starting dose and after six weeks get another blood test and most probably another rise.
It is important that your thyroid gland hormones a tip-top and you will have to make sure during pregnancy that you are sufficiently medicated. We all have to read and learn unfortunately in order to keep/get well.
If you fill in a little of your medical history in your Profile, it will give members an idea, i.e. when diagnosed etc. etc. This is a link for information but links within may not work as Dr Lowe died last year.
Always get your blood tests for your thyroid gland as early as possible (TSH is higher then). Don't take levothyroxine until after your blood test. (If you've eaten you must leave 2 hours either side of the medication).
Take meds with one glass of water and wait about 1 hour before eating.
If you take supplements or other medication take about 4 hours apart from levo. Usually supplements have to be taken with food.
Always ask for a print-out of your blood test results from the surgery, we are entitled, for your own records and make sure they have the ranges alongside the results. You can then post them if you have a query for comments.