Short answer: If you have hypothyroidism or Hashimoto's and you're hoping to get pregnant, you're right to ask about your thyroid before you start trying. The American Society for Reproductive Medicine (ASRM) writes in its patient fact sheet that hypothyroidism may cause the release of an egg less frequently or not at all, and Mayo Clinic's answer is that there is sometimes a link between hypothyroidism and infertility in women. On milder changes, an American Thyroid Association summary from 2022 (ATA) is plain: "It is currently not clear whether mildly abnormal thyroid hormone levels cause infertility". The Office on Women's Health (OWH) adds that "it is especially important to check for problems before getting pregnant and during pregnancy", and the ATA's patient brochure lists planning to get pregnant as a reason to call your doctor. Which tests you need, and when, is your doctor's call.
Maybe you've been treated for years and nobody has said whether anything changes when you start trying. Maybe your cycles have gone irregular and you're wondering about your thyroid. You're allowed to want a plan first.
For how hypothyroidism can change your cycle and ovulation, see hypothyroidism and your period. Everything from a positive test onward is in Hashimoto's and pregnancy.
Osmi's lab album puts every blood result on its own card, shown against the range your own lab printed. Osmi doesn't diagnose anything; it files each result with its unit, date, lab and printed range, and a re-draw stacks on the same card and shows what moved.
What each US body says
Each body words it differently, and the verb tells you how sure it is.
| Body | What it says about hypothyroidism and getting pregnant | Its verb |
|---|---|---|
| ASRM, patient fact sheet | Hypothyroidism can prevent the release of the egg from the ovary, and may cause the release of an egg less frequently or not at all | "can prevent", "may cause" |
| ASRM, 2024 clinician guideline | Overt hypothyroidism can potentially have a significant impact on reproductive outcomes; there is insufficient evidence to counsel women that subclinical hypothyroidism is associated with infertility | "can potentially have", "insufficient evidence" |
| ATA, 2022 study summary | Abnormal thyroid hormone levels and autoimmune thyroid disease may have impact on fertility, especially with overt hyperthyroidism and hypothyroidism; for mildly abnormal levels it's not clear | "may have impact", "not clear" |
| ATA, patient brochure | Call your doctor if you are planning to get pregnant | "Call your doctor" |
| Mayo Clinic | There is sometimes a link between hypothyroidism and infertility in women | "sometimes" |
| OWH | Hypothyroidism can make it harder to get pregnant, and it's especially important to check for problems before getting pregnant | "can make it harder", "especially important" |
| NIDDK | Hypothyroidism can cause fertility problems, and women who have trouble getting pregnant often get tested for thyroid problems | "can cause", "often get tested" |
| Cleveland Clinic | People with an underactive thyroid (especially primary hypothyroidism) have an increased risk of infertility | "increased risk" |
| ACOG, prepregnancy FAQ (medical conditions in general) | You may need to make some changes to bring your condition under control before you try to get pregnant | "may need" |
Across these bodies, two kinds of sentence sit side by side: what hypothyroidism can do to ovulation, and how much is still not known. Neither is a verdict on your own body.
What's settled and what isn't
There are two questions tangled together here, and the bodies answer them with different confidence.
Hypothyroidism and ovulation. ASRM's fact sheet says hypothyroidism can prevent the release of the egg from the ovary. In OWH's telling, problems with thyroid hormone can upset the balance of the hormones that cause ovulation. Neither page says how severe. ASRM's 2024 guideline, written for clinicians, is the one that names overt hypothyroidism, which it says "can potentially have a significant impact on reproductive outcomes." On this part, the bodies point the same way.
Milder changes and antibodies. Here the bodies are open that the evidence isn't settled. ASRM's guideline describes subclinical hypothyroidism as a TSH above the upper limit of the normal range with free T4 still inside it, and says there is insufficient evidence to counsel women that it's associated with infertility. It adds that debate persists about how to define it and when to screen and treat, particularly for women attempting pregnancy. The ATA's 2022 summary says the "potential impact of mild thyroid hormone abnormalities and thyroid autoimmunity on fertility has not been clear", and notes that the study it summarized was limited to Chinese patients.
Miscarriage is where two ASRM documents read differently. Its patient fact sheet says hypothyroidism can also interfere with the development of an embryo, and that this increases the risk of miscarriage. Its 2024 guideline recommends counseling women that subclinical hypothyroidism is not associated with an increased risk of miscarriage. The fact sheet doesn't split overt from subclinical; the guideline does. Which side of that line your own results sit on is a question for your doctor.
In June 2026 the ATA published updated guidelines covering thyroid disease from preconception through postpartum. Its release says they reflect advances in clinical and scientific evidence since its previous recommendations, issued in 2017, and acknowledges that "portions of the available evidence remain of low to moderate quality". So even the newest guidance rests partly on evidence the ATA itself rates that way.
Questions to ask before you start trying
MedlinePlus keeps a list of questions you may want to ask your health care provider about getting pregnant, including "How will an existing medical condition affect my chances of pregnancy?" OWH suggests you "Bring a list of talking points" so you don't forget anything. Write these down before the visit:
- Will my thyroid condition affect my chances of getting pregnant?
- Given my history, which thyroid tests do you want before I start trying, and when?
- Which range are you reading my results against?
- Have my thyroid antibodies ever been tested, and does that matter for us?
- Who looks after my thyroid while I'm trying: you, my endocrinologist, or both?
- Does anything about my plan change now that I'm trying?
- What should I do the day I get a positive test?
- How long should we try before asking about a fertility evaluation?
On which tests, ASRM's 2024 guideline doesn't recommend universal thyroid screening for everyone attempting pregnancy. It says "aggressive case finding" with TSH screening can be considered for patients at increased risk of overt hypothyroidism, and its list includes a history of prior thyroid dysfunction or surgery and a family history of thyroid disease. It also says TSH and T4 should be tested in patients with signs or symptoms of hypothyroidism, including irregular menstrual cycles.
On which range, Osmi doesn't have a TSH number for trying to conceive. ASRM's guideline recommends using laboratory-specific TSH cutoffs, and MedlinePlus tells you to check the reference range listed on your lab report, since you can't compare your results to reference ranges you might find elsewhere. So bring that report, with the range your lab printed on it.
If you're already treated and now trying
If your results have looked steady for a while, it's easy to assume nothing needs to change. The ATA's patient brochure and Mayo Clinic still put you on the call-your-doctor list.
The ATA's patient brochure says to call your doctor if "You are planning to get pregnant or are already pregnant". Mayo Clinic's advice reads: "If you have hypothyroidism and hope to become pregnant, work with your doctor to make sure your hypothyroidism is under control. Seek additional help from an infertility specialist if needed."
ACOG, speaking of medical conditions in general, adds a line that fits here: "Even if a health problem is well managed, the demands of pregnancy may cause it to get worse." OWH lists managing health problems such as thyroid disease among the things to talk about before pregnancy.
The ATA's brochure also asks you to tell your other doctors about your thyroid condition, so the doctor who looks after your thyroid and the one planning the pregnancy both know. What changes, if anything, is your doctor's call. Your part is to ask early.
Hashimoto's and antibodies
ASRM's fact sheet says Hashimoto's thyroiditis, an autoimmune disorder, is the most common cause of hypothyroidism in the US, and that thyroid autoantibodies are seen in patients with it. Those antibodies are measured with a blood test. OWH puts it simply: "Some women with Hashimoto's disease have problems getting pregnant."
On antibodies, the bodies speak to different questions.
The ATA's brochure, on pregnancy. Speaking of pregnancy rather than conception, the ATA's patient brochure lists complications of untreated or inadequately treated hypothyroidism, then says "Some risks also appear to be higher in women with antibodies against thyroid peroxidase (TPO)."
ASRM's 2024 guideline, on the evidence. ASRM's 2024 guideline describes "intermediate-quality and conflicting evidence that is insufficient to suggest an association between thyroid antibodies and miscarriage." It doesn't recommend screening for thyroid autoimmunity in women with infertility who have no symptoms, and says targeted screening may be considered in women with a history of recurrent pregnancy loss. The ATA's 2022 summary says the impact of thyroid autoimmunity on fertility has not been clear.
So these lines answer different questions, and none of them settles yours. If you've never had your antibodies tested, or you don't know, ask whether it matters for you, in those words. For what the antibody tests are and when they're done, see thyroid antibodies explained.
What to have ready
ACOG says a prepregnancy visit covers your medical and family history and past pregnancies. Bring:
- Your cycle start dates for the last few months, especially if your cycles are irregular.
- Your last thyroid results, each with the date of the draw and the range printed on that report. MedlinePlus says you can't compare test results from different labs.
- Whether your antibodies were ever tested, and when.
- Past pregnancies and any losses. MedlinePlus suggests asking whether a previous miscarriage will affect your chances of conception.
- Family history of thyroid disease.
- Who manages your thyroid today, with their name.
Osmi isn't a fertility app and doesn't do ovulation windows or predictions. It keeps your cycle day on the same dated record as your symptoms and your labs. The daily check-in takes about a minute: answer 7 questions or speak with Rose, your thyroid mascot, and every answer lands on the same record as your labs, cycle, and sleep.
When it's time to go in, the appointment sheet is one page, built from the record you already keep, that you share with your practitioner in one tap. It doesn't diagnose anything and it doesn't read your results for you; it puts your own numbers in the order you'll need them. Your questions stay yours to bring, so take your written list in alongside it. Past pregnancies and family history are yours to write down in your own words. For the rest of the visit, see walk into your thyroid appointment with a real record.
Please see your doctor before you start trying, and again if anything about your cycle or how you feel changes. What your results mean, and what to do next, is their call.
One small thing for today: find your last thyroid report and put it with your list of questions. We hope the visit goes well.
Questions women ask about trying to conceive with hypothyroidism
Can I get pregnant if I have hypothyroidism? ASRM's patient fact sheet says hypothyroidism may cause the release of an egg less frequently or not at all. Mayo Clinic's answer is that there is sometimes a link between hypothyroidism and infertility, and OWH writes that it can make it harder to get pregnant. How that applies to you is a question for your doctor, with your own results in front of them.
Does Hashimoto's make it harder to get pregnant in the first place? OWH says some women with Hashimoto's disease have problems getting pregnant, and NIDDK lists fertility problems among the symptoms of hypothyroidism on its Hashimoto's page. On antibodies and miscarriage, ASRM's 2024 guideline calls the evidence conflicting and insufficient, and the ATA's 2022 summary says the impact of thyroid autoimmunity on fertility has not been clear. Ask your doctor whether your own history changes anything.
I'm already treated for hypothyroidism. Does anything change when I start trying? The ATA's patient brochure says to call your doctor if you're planning to get pregnant, and Mayo Clinic says to work with your doctor to make sure your hypothyroidism is under control. ACOG, writing about health problems in general, notes that even a well managed one may get worse with the demands of pregnancy. Ask whether anything about your plan changes now that you're trying.
When should I book a preconception visit if I have a thyroid condition? OWH says preconception care should begin at least three months before you get pregnant, and that some women need more time. ASRM's natural fertility fact sheet says anyone with a medical condition should seek advice from a medical professional before conceiving. If you're already thinking about it, that's a good time to call.
Should my thyroid antibodies be checked before I start trying? The bodies answer different parts of this. The ATA's patient brochure, writing about pregnancy, says complications of untreated or inadequately treated hypothyroidism are more likely in women with severe hypothyroidism, and that "Some risks also appear to be higher in women with antibodies against thyroid peroxidase (TPO)". ASRM's 2024 guideline doesn't recommend screening for thyroid antibodies in women with infertility who have no symptoms, and says targeted screening may be considered after recurrent pregnancy loss. Ask your doctor whether testing matters for you, in those words.
Before I start trying, who should I see: my ob-gyn, my endocrinologist, or a fertility specialist? ACOG describes the prepregnancy visit with your ob-gyn or other obstetric care provider. Mayo Clinic says to work with your doctor and to seek additional help from an infertility specialist if needed. The ATA's patient brochure says to tell your other doctors about your thyroid condition, so whoever looks after your thyroid should know your plans too.
Educational, not medical advice.
