Undiagnosed thyroid disorders can cause fertility difficulties for both men and women, and problems during pregnancy. Once treated, normal fertility returns and you can expect to have a healthy baby.

What should I know?

It is very important to arrange to have a thyroid function test at your GP surgery if you have a thyroid disorder and are planning to conceive, or as soon as you know you are pregnant. Your doctor will take a blood test and then monitor your thyroid levels throughout your pregnancy.

Hypothyroidism

• Keep taking the levothyroxine throughout pregnancy
• Your doctor may increase your levothyroxine dose during pregnancy
• After your baby is born you should have a blood test. Your levothyroxine dose may be altered

Graves’ Disease (Hyperthyroidism)

• Tell your obstetrician about your thyroid disorder
• If you are taking anti-thyroid medication continue to take it
• Your anti-thyroid drug may be changed from carbimazole to propylthiouracil
• Radioactive iodine treatment should not be used during pregnancy
• ‘Block and Replace’ therapy should not be used during pregnancy
• Thyroid surgery should only be performed during the middle three months of pregnancy

After your baby is born

• All new born babies have a heelprick blood test to check for hypothyroidism
• You should arrange a blood test to check your thyroid hormone levels
• You can safely breastfeed whilst taking levothyroxine
• Speak to your doctor if you wish to breastfeed whilst taking anti-thyroid medication
• Postpartum thyroiditis – a temporary thyroid disorder in the mother - may occur up to four months after birth

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