Hypothyroidism in second trimester

I had hyperthyroidism for a decade and was normal for 1-2 years. Recently diagnosed with hypothyroidism in my second trimester and gynae asked me to eat thyroxine. I checked back with my usual endocrine doctor and he say my readings are actually normal (they usually refer to T4 and TSH) Do anyone know if your gynae looks at “free T3 or T4 readings? My T3 is Low but T4 and TSH is of normal readings.