Q: I am a 34 years old and 4 months pregnant woman having hyperthyroidism. I feel severe cold and palpitation and my skin is becoming dry too. I have started taking medication for hyperthyroidism. I hope it will not affect my child. What would be the diet for me so that I control palpitations and bear the cold?

A:

• The diagnosis of hyperthyroidism in pregnant women should be based primarily on a serum TSH value <0.01 mU/L and also a high serum free T4 and free T3 values.
  
  Symptoms associated with pregnancy are similar to those associated with hyperthyroidism, including increased heart rate (tachycardia), heat intolerance, increased perspiration, and weight loss despite a normal or increased appetite. More Specific findings such as enlarged thyroid gland and thyroid eye disease and weight loss suggest Graves' hyperthyroidism.
• Beta blockers (like Atenolol) starting with 25 mg assuming there is no contraindication to it-discuss with your doctor - may be given to relieve symptoms like palpitation of hyperthyroidism in pregnant women. It should be weaned as soon as the hyperthyroidism is controlled by the anti thyroid medication and definitely towards the end of pregnancy as its not safe. Neonatal growth restriction, low blood sugar (hypoglycaemia), respiratory depression, and slow heart rate (bradycardia) have been reported after maternal administration. Discuss with your doctor.
• New recommendation for treatment should be Propthiouracil rather than methimazole in the first trimester and it should be switched to methimazole at the start of the second trimester till the end of pregnancy as propylthiouracil has risk of liver failure.
• Thyroid function should be monitored with free T4 and free T3 concentrations in the high-normal range and serum TSH concentrations in the low-normal or suppressed range.
  
  Average dose of Propylthiouracil should be 50 mg twice daily and with Neomercazole 5-10 mg per day. A higher dose can result in enlargement of the thyroid in the developing baby and hypothyroidism.
• The main risk is enlarged thyroid gland and increased heart rate in babies. All babies of women with hyperthyroidism should be monitored for signs of fetal thyrotoxicosis by determination of fetal heart rate and assessment of fetal growth.