High TSH prior to conception

My DH and I are in our third month of TTC for #1. I had routine blood work done by my PCP and my TSH came back at 5 (T3/T4/Ab all normal). I have never had my thyroid tested in the past, so this is a new finding. I know of the risk of miscarriages with unregulated thyroid, I have not had any (yet) to my knowledge, but I'd like to be optimally managed prior to conception. My questions are, 1) Has anyone else with a TSH of 5 been started on medications or was it just watchful waiting? 2) who should I set up a referral with to evaluate and manage? My PCP? My OBGYN? An Endocrionologist? a Reproductive Endocrinologist?