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Hyperthyroidism & Fertility

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If you are trying to get pregnant, you know your pregnancy starts with an egg and a sperm, but quite a few mechanisms in the body need to be up to par before that union can happen successfully. Your thyroid, a flat, small gland in your neck, is one of those mechanisms. It controls hormone production that helps the body regulate how it uses energy. A hyperactive thyroid produces too many hormones, and your body can end up using energy too quickly. Thyroid disease can put a damper on your quest to get pregnant and can cause a variety of other symptoms throughout your body.

Graves' Disease, one of the few possible causes of a hyperactive thyroid, can cause symptoms like trouble sleeping, hand tremors, brittle hair and weight loss. The disease can cause infrequent periods in women and lower sperm counts in men, which can ultimately cause problems getting pregnant. There is good news, though. A simple test from your doctor or endocrinologist can test your levels and lead to a quick diagnosis and treatment plan that typically includes antithyroid medication. Hormone levels generally return to normal after treatment, and pregnancy is achieved more easily. In extreme cases, radioactive iodine or surgery is used to kill or remove the thyroid before pregnancy. Doctors recommend waiting six months to get pregnant after radioactive iodine treatment.

If you are currently under treatment for Graves' Disease, the Thyroid Foundation of Canada suggests making sure your pregnancy is planned because of possible medication complications to fetal or maternal health. Work with your doctor when you start trying to conceive so that your medications can be reviewed and the dosages can be lowered if necessary. If you plan your pregnancy with your doctors, you will lower your chances of any hyperthyroidism complications with pregnancy, such as miscarriage, preeclampsia or preterm birth.

Once you are pregnant, your body will automatically supress the immune system, which can help with your symptoms. Most pregnant women with hyperthyroid issues will require a lower dosage of medication because the body simply does not need the pre-pregnancy dosage due to the changes that pregnancy brings. Or, they will need to switch medication if they are taking Methimazole, which is the generic version of Tapazole. Although there is no clear link between Methimazole/Tapazole and fetal problems, the preferred medication during pregnancy is Propylthiouracil, according to the Thyroid Foundation of Canada. Your doctor will also monitor you for liver dysfunction while taking the antithyroid medication during pregnancy.

Once you have given birth, your doctor may adjust your medication as your hormones regulate back to normal. If you are breastfeeding, be sure to inform your doctor, but most antithyroid medications are very safe for a nursing mother to take, as only a fraction of the medication actually passes through the breastmilk.


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