Why are thyroid/hormone conditions listed as contraindications for this treatment?

Thyroid condition and general limitations to ultrasonic fat cavitation and radiofrequency (35 y/o female. Mild hypothyroidism now considered in normal range, but can't lose weight, plateau 1yr. after losing 25kg. 1) Why are thyroid/hormone conditions listed as contraindications for this treatment? 2) If I loose more weight overall later (12kg goal) will I be able to do cavitation and RF again? 3) If I ever gain weight, will I gain it in other places (because the fat cells are destroyed)? 4) What if I get pregnant, can I do it again afterwards? Thank you!