High TSH while breastfeeding

[ladylush]

Recent thyroid function test shows a TSH of 17 and a normal T4 (15). I am exclusively bf my 6 mo. Her weight gain was a concern last month and I felt my supply had dropped so started taking Domperidone to boost supply. I think this has helped but am wondering if the high TSH may have affected my supply. Or would this only happen if the T4 was low? TIA

Forgot to add that I am already on thyroxine as sub-clinical hypothyroidism was diagnosed when I was trying to conceive. However the TSH was not as high then (7).