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Most people make a full recovery and feel completely better once their hormone levels get back to normal. But don’t worry if it takes a few months for your symptoms to disappear after starting treatment – this is to be expected. Some people find that they don’t feel completely better until about six months after their hormone levels get back to normal.
Around one in every 20 people with an underactive thyroid will still have some symptoms even when their hormone levels are normal. If this happens, your GP may arrange for you to have further tests to see whether something else is causing your symptoms.
Yes, you can take levothyroxine when you’re pregnant, and it’s important to have the right amount of thyroid hormones in your bloodstream during pregnancy. While you’re pregnant, your body usually needs more thyroid hormone. Because of this, your doctor may need to increase the amount of levothyroxine you take.
Thyroid hormones are important for your baby’s development right from the beginning of pregnancy. So, if you know you have an underactive thyroid, tell your GP as soon as you think you’re pregnant. You’ll need to have regular checks every six weeks during your pregnancy to make sure your thyroid hormones are at a healthy level.
After your baby is born, the amount of levothyroxine you need to take should go down again.
It’s understandable to worry about your weight if you have an underactive thyroid because many people do put weight on. Having an underactive thyroid means that your metabolism will be slower, so you’ll use less energy (calories). But this doesn’t seem to be the main cause of weight gain with an underactive thyroid. Much of the weight gain is because your body holds on to more water than usual, rather than because you’re storing fat.
When you start treatment, you can expect a small amount of weight loss as your body no longer holds onto water. But you may not see a large weight loss because your weight is determined by many factors over time, not just your thyroid hormones. If all your other symptoms of an underactive thyroid get better, but you still have excess weight, this probably isn’t due to your thyroid condition.
If you want to keep your weight healthy, it’s important to eat the right foods and be active. For tips and advice on healthy eating, exercise and how to lose weight safely, see our section: Related information.
If your weight changes a lot, see your doctor. They may need to change the amount of levothyroxine you take.
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