hypothyroidism, BBT & ?preggo

I have been temping for several months. In prior months after ovulation, my temp would rise to around 98 and slightly above. This month several things changed---I am 8/9DPO/IUI (my first), had a HCG trigger on 2/3 so I know that I ovulated. My waking temps are ranging from around 97.7--I have had no change in sleeping habits, etc. I know that my endocrinologist has to adjust my thyroid med when I become preggo. My last thryoid panel in Oct. was normal. My question is would being preggo make my temps stay low unlike the months before?