Can Thyroid Cause the Risk of Miscarriage?

Thyroid and Risk of Miscarriage

Although pregnancy is the most blissful time of a woman’s life, it has its set of complications. Women have to go through various complications, and one such is related to the endocrine gland called the thyroid. This is a small gland which secretes thyroid hormones and is located in your neck.

There are times when your thyroid gland makes excess hormones or very little hormones. These conditions are known as hyperthyroidism (excess hormones) and hypothyroidism (fewer hormones). The hormones released by the butterfly-shaped thyroid are essential because they regulate the use of energy in your body, thereby affecting the function of almost every other organ in the body. Unregulated thyroid glands can cause bodily functions to speed up or slow down drastically. This leads us to the crucial question- can thyroid problems cause miscarriage?

How Thyroid Increases the Risk of Miscarriage

Thyroid problems have long been associated with spontaneous loss of pregnancy, also known as a miscarriage. The connection between thyroid and miscarriage has long existed, especially if you have a hypothyroid condition. There is an increased risk if you have Hashimoto’s disease, an autoimmune disease that affects thyroid function. Hyperthyroid conditions can also lead to miscarriage if not appropriately treated. You could be affected in the following ways:

  • Luteal defects and ovulatory problems are higher if you have a thyroid condition.
  • Pregnant women require an increase in thyroid hormones for foetal development and thyroid dysfunction can hamper this.
  • Hashimoto’s can prevent immunological changes required in the body to support a healthy pregnancy.

1. Miscarriage Risk Due to Hypothyroid

Many women are troubled with the question – can low thyroid cause miscarriage? Hypothyroidism can increase risks of miscarriage, anaemiapreeclampsia, congestive heart failure, or stillbirth. Normal levels of thyroid hormone for pregnancy stand at less than 2.5mlU/L during the first trimester and below 3.0mlU/L throughout the rest of the pregnancy. Anything less than this should be treated. If you have mild hypothyroidism, you may require monitoring but no treatment. Treatment will include supplementing your T4 with T4-mimicking hormones for women with very low levels of TSH. You can further help yourself by having a comprehensive thyroid screening if you have a family history or previous miscarriage due to thyroid conditions.

2. Miscarriage Risk Due to Hyperthyroid

Levels that are higher than 5.0mlU/L during pregnancy require treatment for hyperthyroidism. The only possible treatment of hyperthyroidism during pregnancy is the minimal use of antithyroid drugs to maintain the T3 and T4 levels during pregnancy. Radioactive iodine which is the normal course of treatment needs to be avoided as it can cross the placental barrier and harm the foetus. Untreated hyperthyroidism can cause foetal tachycardia, premature birth, stillbirth, or pregnancy loss in the first trimester.

A doctor examining a woman for thyroid

Measures to be Taken to Avoid Miscarriage Due to Thyroid

Here are some tips for thyroid and pregnancy loss:

1. Comprehensive Thyroid Screening

People with family history and previous complications should have comprehensive screening.

2. Thyroid Hormone Replacement Medication

Hypothyroidism with TSH above 10.0 requires treatment.

3. Plan your Pregnancy

If you are hypothyroid, then plan your pregnancy well and keep your TSH is in the target range. Increase the dose of your medication when pregnancy is confirmed.

4. Test for Pregnancy Early

Test for pregnancy as early as possible and start medication if you have hypothyroid. This is because underactive thyroid and miscarriage go hand in hand. There are tests that can show results within 7 days of conception. Knowing early will help you start treatment on time.

5. Have Periodic Evaluations

Take periodic tests during your pregnancy and adjust the dose of medication to suit you.

6. TPOAb Conditions Require Treatment

TPOAb-positive (Auto-antibodies to thyroid peroxidase) patients require thyroid hormone-replacement treatment early in the pregnancy.

7. TPOAb Positive Condition

If you are TPOAb-positive with a history of recurring pregnancy loss, you should be treated accordingly.

8. ART Procedures for Conception

ART (Assisted Reproductive Techniques) procedure patients like IUI or IVF who have subclinical hypothyroidism should start treatment before pregnancy.

9. Overtly Hyperthyroid Condition

Overtly hyperthyroid conditions during pregnancy require treatment with antithyroid drugs.


Frequently asked questions related to hypothyroidism, early miscarriage, and hyperthyroidism have been explained below:

1. What is a Good Thyroid Level for Pregnancy?

Thyroid levels during pregnancy should be between 2.5mlU/L to 3mlU/L throughout the gestation period.

2. If I am Treated for Hypothyroidism, How Can I Lower My Risk of Miscarriage?

You should be vigilant and take a comprehensive screening. You must also get tested periodically throughout your gestation period and have your doctor alter your dose according to your needs.

It is unquestionably possible to have a healthy pregnancy and deliver a beautiful baby even if you have thyroid conditions. What is important is to be aware of your condition and take the required medication. Do not feel stressed because this can only worsen your hormone levels and put you at greater risk. Work closely with your doctors and healthcare professional to get all the help you require. Equipped with the knowledge and the right medication, you should sail through your pregnancy and have your little one soon enough!

Also Read:

Risks of Miscarriage during Pregnancy
Effective Tips for Avoiding a Miscarriage
Incomplete Miscarriage

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