Hi Doctor, I M Pregnant , My Last Missed Period

Hi Doctor, i m pregnant , my last missed period date was Dec 24th, I m taking the tablets for hypothyroidism for the past 2 years. Taking the tab Thyronorm 75mcg. On november month i did the last TSH test. At that time it was 3.98. After pregnant i consult a doctor and tell about this also. She asking me to continue the same tab. Is need to increase the dozage of medicine in this time