Can You Be a Surrogate With a Thyroid Condition?

Thyroid conditions are common, and a lot of women on thyroid medication assume that settles it. Usually it doesn't. Here's what clinics actually look at.

Published October 13, 2026

Often, yes: a thyroid condition that's well controlled, such as hypothyroidism treated with levothyroxine, doesn't by itself rule you out. What clinics want to see is stable thyroid levels on a pregnancy-safe treatment plan, and active hyperthyroidism or recent radioactive iodine treatment usually means waiting until things have settled.

Thyroid conditions are among the most common things we see in health histories. According to the American Thyroid Association, Hashimoto's thyroiditis is the most common cause of an underactive thyroid (hypothyroidism) in the United States, and Graves' disease is the most common cause of an overactive thyroid (hyperthyroidism) in women of childbearing age. If you're managing either one, you're far from unusual.

What ASRM says

ASRM's Practice Committee guidance on gestational carriers doesn't single out thyroid disease. What it does say is that before acceptance, a potential carrier should undergo a complete medical evaluation by a qualified medical professional, including preconception counseling and evaluation, and its Ethics Committee describes carriers as people who should be healthy. In practice, many clinics include thyroid function in their screening bloodwork, so your thyroid may be checked whether or not you've ever had a problem.

Hypothyroidism and Hashimoto's

If you take levothyroxine and your levels are in range, this is usually a manageable part of your history rather than a barrier. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says plainly that "Levothyroxine is safe for your baby." The important part is that pregnancy raises the body's need for thyroid hormone:

• The dose usually goes up. NIDDK says women who took levothyroxine before pregnancy will probably need a higher dose, and that many thyroid specialists recommend two extra doses per week, starting right away.
• Levels are checked often. NIDDK describes thyroid checks every 4 to 6 weeks in the first half of pregnancy, with the dose adjusted as needed.
• The plan is made in advance. In a surrogate pregnancy the timing is known from the transfer date, so your doctor and the clinic can agree on how your dose will be handled before the transfer instead of after a positive test.

The reason clinics care about control is that, according to NIDDK, uncontrolled hypothyroidism can lead to preeclampsia, anemia, miscarriage, low birthweight and stillbirth, most often when it's severe. Well-managed thyroid levels are what make the rest of the conversation easy.

Hyperthyroidism and Graves' disease

An overactive thyroid needs more care before a pregnancy. NIDDK lists miscarriage, premature birth, low birthweight and preeclampsia among the problems uncontrolled hyperthyroidism can cause. Graves' disease adds one more consideration: the antibodies involved can cross the placenta and affect the baby's thyroid, which is why NIDDK advises telling your doctor if you've had radioactive iodine or surgery for Graves' so your antibody levels can be checked.

• Active hyperthyroidism usually means "not yet." Clinics will typically want your thyroid function back to normal and stable before moving forward.
• Radioactive iodine has a waiting period. American Thyroid Association guidance advises allowing time for clearance, 6 months, before conceiving after radioactive iodine treatment, and some clinics may ask for longer.
• Antithyroid medication is a specialist decision. Which medication is used around early pregnancy, and when, should be planned with your endocrinologist, and the clinic will want to see that plan.

After thyroid surgery or thyroid cancer

If your whole thyroid was removed, you'll take thyroid hormone for life, and from a pregnancy standpoint that is managed much like hypothyroidism. If the surgery was for thyroid cancer, the clinic will usually want records from your treating doctor, including when treatment ended and any follow-up plan, before deciding. That's a case-by-case medical review, so the most useful thing you can do is have the paperwork ready.

How to prepare

• Gather your recent lab results, with dates, so the clinic can see your levels over time and not just a single reading.
• Know your diagnosis and history: what condition you have, when it was diagnosed, and any treatments such as radioactive iodine or surgery, with dates.
• List your current medication and dose, and when the dose last changed.
• Ask your doctor for a short note confirming your condition is stable and how they'd manage your dose in a pregnancy.
• Mention your past pregnancies: whether your thyroid was treated during them and how they went.

Where this comes up with Borne

Our questionnaire asks about your health conditions and medications, and on the screening call we'll ask how your thyroid is managed and how stable it's been. If your history fits, we'll connect you with partner agencies, and the final medical decision always belongs to the clinic's doctor after reviewing your records.

The bottom line

A thyroid condition is common and, when it's well controlled, often compatible with surrogacy. Keep your levels stable with your doctor, wait out any required time after radioactive iodine, and bring your records. That's usually what turns a worry into a routine part of your medical review.