PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC9191263
Outcomes With Levothyroxine Treatment in Early Pregnancy With Subclinical Hypothyroidism - PMC
Several observational studies and meta-analyses reported the risk of miscarriage, gestational hypertension, placental abruption, pre-eclampsia, gestational diabetes, intrauterine growth restriction (IUGR), preterm birth, and low birth weight (LBW) [8-10]. Therefore, it is imperative to initiate ...
GoodRx
goodrx.com › goodrx health › drugs › levothyroxine › levothyroxine and pregnancy: what you need to know
Levothyroxine and Pregnancy: What You Need to Know - GoodRx
March 23, 2022 - Is levothyroxine safe during pregnancy? Yes. People with hypothyroidism should take levothyroxine if their healthcare provider recommends it. Learn how it can support your pregnancy here.
Impact of Levothyroxine on Symptoms & Pregnancy
I’ve had 3 healthy pregnancies with hashimotos. In fact, the hashimotos gets BETTER when pregnant. Post partum is where hell breaks loose for me More on reddit.com
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January 1, 2024Levothyroxine/Hypothyroidism and Pregnancy Loss Worry
Yeah you should get it checked sooner rather than later. I tried to since I was born without a thyroid, but my doctors dismissed it till 10 weeks. My TSH skyrocketed to 7 because it wasn’t being managed for so long to the point i was having late stage hypo symptoms, but I’ve seen lots of others post on here with even higher numbers. My endo (who I wasn’t seeing before pregnancy because my levels have remained stable on the same dose for the past 10+ years) said she tells all patients to start taking one-two (I can’t remember) additional pills per week as soon as they find out their pregnant even before getting in for an appointment. A lot of the risk is if you failed to manage it for the duration of the entire pregnancy. I would just get in for a TSH check ASAP (see if your doctor can call in bloodwork) and ask to have it tested every four weeks from here on out. But don’t freak out and take extra right now unless your doctor advises, because there’s a much worse risk to the baby from thyroid toxicity and it’ll mess up your numbers when you do test. More on reddit.com
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December 3, 2021Hypothyroidism ladies of Reddit
Mine was only raised from 75mcg daily to 75mcg 6 days p/wk and 150mcg 1 days p/wk 1st trimester, so not 30%. I think it depends greatly on your body size and where your levels currently are. We've adjusted the dose down briefly and then up again. I'd bring it up with them and make sure they are checking your levels but not stress too much about specific percentages. More on reddit.com
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December 31, 2022Levothyroxine and Pregnancy -- dosing mistake
I have definitely accidentally taken my Levo twice in a morning a couple times this pregnancy. I’ve also totally forgotten to take it before (or thrown it up). I figure it levels out over time 😆. I never even called my OB about it. Levo is so safe during pregnancy and an accidental double dose one time won’t hurt anything, especially since you ate shortly after. I’m 35 weeks now and all’s good with lil one. Deep breath mama. You’ll be okay. More on reddit.com
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January 14, 2019Videos
00:38
Is it safe to take thyroid medication in pregnancy? - YouTube
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Do I need levothyroxine with subclinical hypothyroidism in pregnancy?
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South West Maternal Medicine Network: Hypothyroidism during pregnancy ...
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How is hypothyroidism managed in pregnancy? by Dr Catherine Napier ...
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Is it safe to take thyroid meds in pregnancy? by Dr Catherine Napier ...
NHS
nhs.uk › medicines › levothyroxine
Levothyroxine: a medicine for an underactive thyroid (hypothyroidism) - NHS
Visit the Yellow Card website for more information about reporting side effects. Levothyroxine is safe to take in pregnancy. It's important to carry on taking levothyroxine throughout your pregnancy.
American Thyroid Association
thyroid.org › home › patients portal › clinical thyroidology for the public › october 2016 › vol 9 issue 10 p.5-6
Increasing levothyroxine doses early in pregnancy is associated with a lower risk for pregnancy loss in hypothyroid women
October 9, 2016 - The information about the age, body mass index, medical conditions, ethnicity, level of education, employment, smoking and use of illegal drugs, complications and course of pregnancy was obtained by reviewing medical charts The patients were divided into two groups; group 1 consisted of 85 women who had immediate increase of Levothyroxine dose after the thyroid blood test in first trimester of pregnancy showed abnormal TSH and group 2 consisted of 11 women who did not have any adjustment in levothyroxine dose.
Mayo Clinic
mayoclinic.org › drugs-supplements › levothyroxine-oral-route › description › drg-20072133
Levothyroxine (oral route) - Side effects & dosage - Mayo Clinic
October 1, 2025 - This medicine is not effective for weight reduction. If taken in large amounts, levothyroxine may cause serious unwanted effects. Hypothyroidism can sometimes cause infertility in men and women.
BioMed Central
bmcmedicine.biomedcentral.com › articles › 10.1186 › s12916-022-02586-9
Association of maternal levothyroxine use during pregnancy with offspring birth and neurodevelopmental outcomes: a population-based cohort study | BMC Medicine | Full Text
November 8, 2022 - Such risk might be confounded by the underlying maternal thyroid disease itself, however, we cannot completely exclude the possible effect of gestational L-T4 treatment on offspring preterm birth. Our findings provided support to the current guidelines on the cautious use of levothyroxine treatment during pregnancy. ... Thyroid diseases are the second most common endocrine disorder in pregnancy, which are broadly categorized into hyperthyroidism and hypothyroidism, with a prevalence of around 0.2% and 2.5%, respectively [1,2,3,4,5,6]. As thyroid physiology is distinctly modified during pregnancy [7], the proper transferal of maternal thyroid hormones to the developing fetus is critical, especially during the early stages of gestation.
BuzzRx
buzzrx.com › blog › what-to-know-about-levothyroxine-and-pregnancy
What to Know About Levothyroxine and Pregnancy
April 15, 2024 - Hyperthyroidism can cause pregnancy complications, but it is possible to treat hyperthyroidism using Levothyroxine during pregnancy. Read more for details.
Jparathyroid
jparathyroid.com › Article › jpd-13297
Adverse side effects of maternal levothyroxine consumption in pregnant women with subclinical hypothyroidism: a systematic review study
August 9, 2025 - Other effects, seizures in children, inadequate gestational weight gain, infant death, premature rupture of membranes, fetal macrosomia, and postpartum hemorrhage, were each noted once. Two studies found no adverse effects. Conclusion: This review study highlights preterm labor as the most ...
Oxford Academic
academic.oup.com › ejendo › article › 192 › 2 › R7 › 8010895
Levothyroxine supplementation trials in preconception and pregnant women | European Journal of Endocrinology | Oxford Academic
February 1, 2025 - TPO antibody positivity and adverse pregnancy outcomes. Best Pract Res Clin Endocrinol Metab. ... Maternal subclinical hypothyroidism, thyroid autoimmunity, and the risk of miscarriage: a prospective cohort study. ... Meta-analysis of the association between maternal subclinical hypothyroidism and gestational diabetes mellitus. Int J Gynaecol Obstet. ... Effect of levothyroxine on miscarriage among women with normal thyroid function and thyroid autoimmunity undergoing in vitro fertilization and embryo transfer: a randomized clinical trial.
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC9745595
The impact of levothyroxine exposure on delivery outcome in hypothyroid pregnant women (PETAL study): A five-year retrospective cohort study - PMC
Based on the results our team previously demonstrated in fundamental research, we could presume a possible additional effect of levothyroxine due to overtreatment in hypothyroid pregnant women of our population.11,12 Some clinical studies also documented an increased risk of CD and labor induction with hyperthyroidism, where women are exposed to high thyroxine serum concentrations due to a pathological overstimulation of thyroid hormone production.21–23 Therefore, a prolonged uterine quiescent phase in late pregnancy could be hypothesized as a cause of fetal breech presentation, in addition
American Academy of Family Physicians
aafp.org › pubs › afp › issues › 2014 › 0215 › p273.html
Thyroid Disease in Pregnancy | AAFP
February 15, 2014 - Overt and subclinical hypothyroidism ... risk of adverse neonatal outcomes, including preterm birth, low birth weight, and increased perinatal morbidity and mortality.12 Childhood neurodevelopment also seems to be contingent ...
UChicago Medicine
uchicagomedicine.org › forefront › news › 2004 › august › excess-thyroid-hormone-harmful-to-fetus
Excess thyroid hormone harmful to fetus
August 10, 2004 - Researchers from the University of Chicago have showed, for the first time, that an excess of thyroid hormone during pregnancy has a direct toxic effect on the fetus, tripling the risk of miscarriage and reducing the average birth weight of infants who survive.
New England Journal of Medicine
nejm.org › doi › full › 10.1056 › NEJMoa040079
Timing and Magnitude of Increases in Levothyroxine Requirements during Pregnancy in Women with Hypothyroidism | New England Journal of Medicine
The results of our study suggest that the prevention of hypothyroidism and its possible adverse effects on the fetus and pregnancy in this population requires the combined efforts of primary care physicians, endocrinologists, obstetricians, and the women themselves. On the basis of our observations, we propose a practical solution: women who are currently being treated for hypothyroidism should be given written instructions to increase their current dose of levothyroxine by taking two extra daily doses during each week (i.e., to increase the dose by 29 percent) beginning the week pregnancy is confirmed and to continue doing so until they are able to undergo thyroid-function testing and obtain appropriate professional guidance.
BMJ Open
bmjopen.bmj.com › content › 8 › 9 › e022837
Impact of levothyroxine therapy on obstetric, neonatal and childhood outcomes in women with subclinical hypothyroidism diagnosed in pregnancy: a systematic review and meta-analysis of randomised controlled trials | BMJ Open
September 1, 2018 - The inclusion of only randomised control trials minimises the bias associated with observational studies in order to clearly evaluate the effects of levothyroxine treatment in pregnant women with subclinical hypothyroidism. Only three trials were identified for inclusion. Subclinical hypothyroidism, generally defined as a thyroid stimulating hormone (TSH) value greater than the upper limit of the reference range with a normal free thyroxine (free T4) and no symptoms of hypothyroidism, is a common biochemical finding in pregnancy, occurring in more than 25% of pregnant women (depending on the assay and reference ranges used).1 It must be noted that the diagnostic criteria for subclinical hypothyroidism in pregnancy have changed over the years and vary between countries.
Vinmec
vinmec.com › home › use medicines safely
Does taking thyroid medication affect the fetus? | Vinmec
July 1, 2025 - Synthetic thyroid hormone medication, such as levothyroxine. This is a drug used to treat hypothyroidism in both men and non-pregnant women. For pregnant women, the dose can be increased by about 25 - 50%. ... Synthetic antithyroid medication, such as carbimazole, methimazole, methylthiouracil (MTU), propylthiouracil (PTU), and thyrozol. Most of these synthetic antithyroid medication have side effects on the fetus, one of which is hypothyroidism in the fetus.
Reddit
reddit.com › r/hashimotos › impact of levothyroxine on symptoms & pregnancy
r/Hashimotos on Reddit: Impact of Levothyroxine on Symptoms & Pregnancy
January 1, 2024 -
I’m recently diagnosed with sub clinical hypothyroidism caused by hashimotos. My TSH is 8.5 and my endocrinologist said that because I’m currently trying to get pregnant she would start me on levothyroxine. She said after 1-2 months my levels should get down and I can start trying again, since there are a lot of negative outcomes for pregnancy and birth with hypothyroidism.
Have folks found that levothyroxine alleviates symptoms? Has anyone had experience being pregnant after being on medication? I’m worried that either the symptoms will still be here after the medication and/or the impact on a developing baby will still be present. I’m in my late 30s so there are already higher risks for developmental difficulties.
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I’ve had 3 healthy pregnancies with hashimotos. In fact, the hashimotos gets BETTER when pregnant. Post partum is where hell breaks loose for me
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Currently 23 weeks pregnant. Been on levo for 14 years. Once your levels are stable, it shouldn’t impact your ability to get pregnant. Make sure they regularly test you during pregnancy as the fetus takes t4 hormone from the mom so you may need to increase dose in first trimester.
Poison Control
poison.org › articles › synthroid-levothyroxine
Synthroid (Levothyroxine): Side effects, Interactions, and Overdose | Poison Control
Because thyroid function can fluctuate during pregnancy, a doctor might need to adjust the dosage of levothyroxine taken during pregnancy. Thyroid hormones can increase the body’s metabolism and promote weight loss. Some people might use their levothyroxine prescriptions for this reason, but it’s important to know that the use of levothyroxine for weight loss can result in dangerous and potentially life-threatening side effects.
MedlinePlus
medlineplus.gov › home › drugs, herbs and supplements
Levothyroxine: MedlinePlus Drug Information
However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. ... shortness of breath, wheezing, hives, itching, rash, flushing, stomach pain, nausea, or swelling of hands, feet, ankles, or lower legs · If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
British Thyroid Foundation
btf-thyroid.org › pregnancy-and-fertility-in-thyroid-disorders
Pregnancy and fertility in thyroid disorders
Read how thyroid disease can affect conception and pregnancy and its management
Healio
healio.com › news › endocrinology › 20201209 › levothyroxine-overtreatment-during-pregnancy-increases-odds-for-preterm-delivery
Levothyroxine overtreatment during pregnancy increases odds for preterm delivery
December 9, 2020 - A cohort of pregnant women in Canada who were overtreated for hypothyroidism with levothyroxine were more likely to have a preterm delivery than women with normal thyroid-stimulating hormone, according to a study published in Thyroid.