Not taking THYRAX can affect your baby if you have hypothyroidism, so take your medication, your TSH in pregnancy must be between 0.3 -2 .
Levothyroxin is safe.
You may need to increase your thyrax dose during the pregnancy. THis is required to keep you and your baby healthy. YOu need to work very closely with your doctor and all will be fine. Most doctors will test your thyroid levels every month while you are pregnant and adjust your meds as required.