Depends...I had terrible thyroid storms with my daughter back in 2006. It caused me to go into heart failure and have to have emergency c-section at 7.5 months. She died 3 days later. She had heart complications and was only 1.5 pounds. Since than, I had to have my thyroid removed. My last pregnancy was okay and he turned out fine on medication. I nursed him until 21 months. He never tested for high thyroid. I had 2 miscarriages in last year due to low thyroid. Now pregnant at 15 weeks 5 days and baby is fine. My thyroid fluctuate's a lot so have to get tested every 6 weeks and adjust medicine. Hope this helped.
I have hypothyroidism and it affects it a little but don't worry. My doctor had to draw blood every month and then I had to have ultrasounds almost every time. The baby's can sometimes grow littler. I have two girls and never had a problem. I got to see my girls way more than most people get to see there kids in the womb
I have hypothyroidism and have had 2 children, this is my third and have never had a problem.. as long as it's well controlled and watched throughout your pregnancy, there isn't a problem!