Thyroid And Pregnancy: How To Support Your Thyroid Before, During And After Baby
During pregnancy, your thyroid works at its peak, more than at any other time in your life. The way your thyroid functions before conception, throughout each trimester, during the first year after giving birth, and in any following pregnancies directly influences your baby's development and your personal recovery journey. So, what should you consider testing for thyroid function, and what questions should you ask your healthcare provider? How can you best prepare your thyroid before conception, and what steps should you take if changes occur along the way?
Floralia practitioners often address questions about thyroid function with patients in the clinic, as managing thyroid health during pregnancy is rarely as simple as just checking TSH levels. If you're planning to become pregnant, are already expecting, or are in the postpartum phase, a personalised consultation at Floralia can help you understand what your thyroid needs during these times.
Why your thyroid matters more in pregnancy than at any other time
The thyroid is a butterfly-shaped gland located at the base of your neck. In pregnancy, the thyroid works very hard indeed. The hormones produced by the thyroid play an important role in regulating body temperature and metabolism, but also, and particularly in this case, in fetal development.
How pregnancy changes thyroid hormone demand
From the moment implantation occurs, your thyroid will be required to make much more thyroid hormone than it normally would. In fact, the increase in demand will be 50% greater or more. The rise in oestrogen levels means that the levels of thyroid binding globulin will also increase, while HCG will also stimulate the thyroid gland.
This explains why even a woman with a perfectly functioning thyroid may begin to exhibit symptoms of stress after getting pregnant. The thyroid gland, which was happily just ticking along as usual, will find it hard to cope with the increased workload. Women who have thyroid problems or poor nutritional levels are bound to be affected more. Women in such cases will definitely require pregnancy support that looks at thyroid function alongside the wider demands of early gestation.
What your baby relies on you for in the first trimester
Thyroid production in the foetus only starts at around week 10 to 12 of gestation and will continue developing until the third trimester. Up until this point, it is completely dependent upon thyroxine from the mother that crosses the placenta into the foetus.
It is important because it is in this period that the baby’s brain and nervous system develop. The maternal thyroid hormone levels during this period are critical for the proper formation of neural connections. Mild deficiencies of the maternal thyroid hormone have been associated with cognitive problems that appear later on in life. This is the biological basis behind the importance of optimising thyroid levels before conception, and why waiting until you visit your doctor for the first time during pregnancy is already too late.
Thyroid testing in pregnancy: what to ask for and why standard ranges fall short
Many women are told their thyroid is fine based on a single TSH reading. However, relying solely on this measurement (especially when evaluated against a broad adult reference range) can overlook many cases of thyroid dysfunction related to pregnancy.
Trimester-specific TSH ranges your lab may not flag
TSH levels should be determined on a trimester-by-trimester basis according to guidelines provided by the American Thyroid Association, since there is a change in the normal range throughout the stages of pregnancy. The TSH level during the first trimester should be lower than the reference range for adults, which can be up to 2.5 mIU/L.
The problem lies in the fact that a lot of Australian laboratories still use a more general range for adults in their reports, which could even go up to 4.0 mIU/L or 4.5 mIU/L. The TSH test result of 3.8 mIU/L during the first trimester will be listed on the report as "normal," although it clearly goes beyond the threshold for treatment. As such, if you're pregnant or want to get pregnant, and have had your TSH result reported as "normal," it would be best to find out more about the exact number and whether it is inside the trimester-specific range for your stage.
Why TSH alone is not enough (free T4, free T3 and TPO antibodies)
TSH tells you what the pituitary gland is asking the thyroid to do. But it does not indicate the level of production by the thyroid, the amount of hormone that is actually in circulation, nor if any autoimmune condition is taking place.
A comprehensive assessment of thyroid function during pregnancy should include both free T4 and free T3, since the former reflects the level of the principal hormone produced by the thyroid, while the latter reflects the active form used by the body’s cells. Thyroid peroxidase antibodies (markers of autoimmune conditions affecting the thyroid) should be assessed, especially in cases of prior miscarriage, family history of thyroid problems, or any signs of fatigue or weight changes. This is the kind of thyroid testing in Perth that Floralia practitioners routinely undertake rather than relying on a single marker.
Approximately 10% of women of childbearing age have TPO antibodies. Most of them have normal TSH levels and feel fine, but their antibody activity causes rapid destruction of the gland when pregnancy increases the need for the thyroid to produce hormones. One test for antibodies (preferably prior to pregnancy) provides knowledge that will change your approach to managing pregnancy right from the start.
When to test if you are trying to conceive
If you are actively trying to conceive, having a full thyroid panel done early in the pre-conception period will allow you to have enough time to address issues. Generally speaking, Floralia practitioners recommend having your TSH, free T4, free T3 and TPO antibody levels checked between three and six months before your planned pregnancy date. That way, you can build up your nutritional status, as well as balance any thyroxine dosages, while getting your TSH within range for optimal fertility results.
When dealing with irregular menstrual cycles, a history of miscarriage, or unsuccessful attempts to conceive for over six months, checking your thyroid function should be a priority. In such cases, conducting hormone imbalance testing alongside a thyroid panel often reveals interconnected patterns that a simple TSH test might miss.
Preparing your thyroid before you fall pregnant
Preconception marks the starting point for prevention. Once that pregnancy test shows positive results, the early neural tube will have developed, and your thyroid glands will have started working. It is possible to give your body a real advantage by optimising your thyroid functioning months before conception.
The preconception window most women miss
The ideal period to start preconception care is three to six months before attempting to conceive. This would be the right period wherein your nutrients and antibodies could be restored to normal levels, and your thyroid medications fine-tuned for pregnancy.
Iodine, selenium, iron, and vitamin D levels can be low in women who have been on birth control pills, women who have recently had a pregnancy, those following a vegan diet, and those with a history of eating disorders. These vitamins and minerals are not just supplements. They are the ingredients that your thyroid gland requires for hormone production, and without them, no matter how much thyroxine you take, your thyroid will not return to proper function. A structured approach with a fertility naturopath in Perth can help map what needs addressing well before you begin trying.
Iodine, selenium and the nutrients your thyroid needs to make hormones
Iodine is a nutrient I'm sure many of us have heard about. Iodine needs increase during pregnancy, reaching an amount of 250 mcg daily. This complies with the guidelines set by the World Health Organisation, where thyroid hormone production needs to be boosted for optimal foetal growth and development. Iodine deficiency during pregnancy can cause brain problems in babies, since iodine is needed to produce thyroid hormones.
A mineral that is not often talked about is selenium, and it is equally as critical as iodine. Selenium acts as a cofactor in an enzyme that helps synthesise T4 hormone into the more active T3 form, as well as playing a vital role in the prevention of free radical injury within the cells of the thyroid gland. Studies show that women with anti-thyroid peroxidase antibodies will see a decrease in their antibody concentrations when taking appropriate amounts of selenium.
Iron status directly influences thyroid hormone production. Women who have low levels of ferritin are unable to sustain healthy T3 levels, despite having appropriate TSH and T4 readings. Many women of childbearing age lack sufficient iron, especially women with heavy menstruation.
Vitamin D functions more like a hormone than as a vitamin, and its deficiency is linked to an increase in autoimmune thyroid disorders. Other necessary nutritional cofactors include zinc and tyrosine. A functional medicine practitioner at Floralia will assess all of these as part of a preconception consultation rather than focusing on iodine alone.
If you already have a thyroid condition: what to sort out before conception
If you already take thyroxine, you should be prepared for the dose to rise, possibly up to 30%-50%, once you become pregnant. Ideally, your TSH should be at the lower levels within the normal reference range of 1.0-1.5 mIU/L before you conceive. Should your current TSH level be 3.5 mIU/L, your GP may discuss increasing your dose beforehand.
If you have Graves' disease or a prior history of hyperthyroidism, planning before conception becomes even more significant, as certain antithyroid medications need to be prescribed during the first trimester and other ones during the latter trimesters.
Hypothyroidism and subclinical hypothyroidism in pregnancy
Hypothyroidism (an underactive thyroid) ranks as the most frequent thyroid issue during pregnancy. It happens when your thyroid makes too little thyroid hormone, and if not addressed, it poses significant risks to both the mother and the baby.
How hypothyroidism affects miscarriage risk and your baby's brain development
Hypothyroidism without treatment has been associated with miscarriage, preterm delivery, low birth weight, preeclampsia, and anaemia. In terms of the foetus, it’s about brain development. It is maternal thyroxine passing the placental barrier during the first trimester that allows for the development of the brain, and a lack of sufficient amounts will have an impact on this process.
The good news is that after a diagnosis and proper treatment of hypothyroidism, most of these risks go away. Women with their hypothyroidism under control give birth to healthy children. The issue isn’t hypothyroidism alone; the issue is unrecognised or untreated hypothyroidism.
Adjusting thyroxine when you find out you are pregnant
If you are taking thyroxine, and you discover that you have become pregnant, then your dose has to be increased at a fast pace. The accepted dosage increase ranges from 30% to 50%, and this is required immediately after confirming the pregnancy.
It's important to consult with your healthcare practitioner once you find out you're pregnant to learn how your dosages will need to be increased.
Thyroid hormone levels need to be tested every four to six weeks during the initial half of pregnancy, so that further adjustments to medication can be made as needed.
What absorbs your thyroxine, and what you need to take separately
The absorption of thyroxine can be easily inhibited by substances commonly consumed by most pregnant women. Iron and calcium supplements will bind the thyroxine in the gut and inhibit its absorption. Both are commonly found in pregnancy vitamins.
To get the most out of thyroxine, take it first thing in the morning before you even get out of bed. Swallow the tablet with just water on an empty stomach. After that, give yourself a 30 to 60-minute buffer before having breakfast or any other supplements. If you take iron or calcium, plan to take them at least four hours apart from thyroxine. And for coffee lovers, make sure your morning brew comes after the medication to ensure proper absorption.
Women who take their thyroxine alongside a pregnancy multivitamin in the morning may not absorb the therapeutic dose of thyroxine as needed. This is one of the main reasons a thyroxine dose might not seem to be effective.
Subclinical hypothyroidism and TPO antibodies: when treatment is recommended
Subclinical hypothyroidism is a condition where the levels of thyroid-stimulating hormone exceed the upper limit of the trimester but have normal free T4 levels. More recent studies have found that subclinical hypothyroidism in pregnancy increases the chances of miscarriages and low birth weight, amongst other complications.
If your TSH levels are mildly raised and you have TPO antibodies, then it would be advisable to start thyroxine replacement therapy. However, if your TSH levels are mildly raised and you do not have any antibodies, then the treatment would depend on your medical history, presenting symptoms, and personal risk factors. It would be beneficial to have this discussion with your doctor, rather than being told your result is "borderline" and left without a plan for managing it.
Hyperthyroidism in pregnancy
Hyperthyroidism occurs less frequently than hypothyroidism during pregnancy, yet it requires attentive management due to its considerable impact on both the mother and the baby.
Graves' disease vs gestational thyrotoxicosis (and why the distinction matters)
Graves’ disease is an immune disorder in which antibodies trigger the production of excessive levels of thyroid hormones from the thyroid gland. The condition affects between one to four women out of every thousand pregnancies and is the most common cause of overt hyperthyroidism in pregnancy.
Gestational transient thyrotoxicosis is different. It is caused by excessive human chorionic gonadotropin in early pregnancy, which stimulates the thyroid gland to produce excessive hormones. This condition is prevalent among pregnant women with hyperemesis gravidarum; it reaches peak severity between 10 and 12 weeks and eventually subsides on its own.
This is an important point since the difference is reflected in how each one is treated. Treatment for gestational thyrotoxicosis doesn’t require antithyroid medications. It is simply managed through monitoring and supportive care. Treatment for Graves’ disease requires treatment. Distinguishing between the two is based on TSH receptor antibody tests, symptomatology, trend in blood values, and severity of morning sickness.
Treatment options in pregnancy and what they mean for your baby
If hyperthyroidism is more severe during pregnancy, antithyroid medications (such as propylthiouracil (PTU) or methimazole) may be administered to decrease production of hormones by the thyroid gland. Methimazole is commonly prescribed for women in their second trimester of pregnancy.
These drugs penetrate the placenta, interfering with foetal thyroid function, which is why the minimum necessary dosage is prescribed. Monitoring helps keep a balance between maintaining the mother's thyroid hormone levels while avoiding excessive suppression of the fetus's.
Hyperthyroidism without treatment poses more dangers than hyperthyroidism with treatment. Hyperthyroidism has been found to be responsible for premature labour, preeclampsia, abruption of the placenta, stillbirth, and heart failure among mothers and babies. A rare condition called “thyroid storm” is one of the less common conditions, but is also a danger and another reason good control is so important.
Why radioactive iodine is off the table
Radioactive iodine treatment is a common method for addressing thyroid issues in non-pregnant individuals. However, it poses serious risks during pregnancy, as it can pass through the placenta and harm the developing baby's thyroid gland. For those considering this treatment for a chronic thyroid condition, it’s crucial to finish the procedure and observe a recommended waiting period before planning to conceive. This precaution helps ensure the safety and health of both the mother and the future child.
Thyroid surgery (which involves the removal of some or all parts of the gland) is not done on pregnant women unless the patient cannot take anti-thyroid drugs or if her condition is too severe for medication alone.
The autoimmune thyroid picture: what conventional care often overlooks
The majority of thyroid dysfunction among reproductive-age women results from an autoimmune response. The majority of hypothyroidism is caused by Hashimoto’s thyroiditis, whereas Graves’ disease causes most cases of hyperthyroidism. Mainstream medicine uses drugs to fix the hormone balance problem, but that is only half of the story. What is not being addressed is why the body’s immune system attacks its thyroid gland?
Hashimoto's, Graves' and the immune shifts of pregnancy
Pregnancy alters the workings of the immune system. Since the body must accept the presence of an embryo that does not share its exact genetics, the functioning of the immune system changes. Pregnant women who suffer from autoimmunity in their thyroid tend to experience a reduction in antibodies, which increases afterwards during the postpartum period.
These changes in immunity help shed light on why a woman feels healthy in her second trimester but suffers after giving birth, or why thyroxine dosages have to be modified some six months later after delivery.
Gut health, stress and nutrient status as drivers of thyroid antibodies
Thyroid antibodies are not just going to pop up for no reason at all. According to the natural medicine model, some of the things that should be looked into include increased intestinal permeability, chronic low-level infections, nutritional deficiencies (selenium, vitamin D, zinc, and B12), and accumulated stress.
Here’s where the value of naturopathic medicine truly comes in. The conventional evaluation tells you that you have Hashimoto’s. The naturopathic evaluation wonders why. What underlying factors may be causing your antibodies to go up? Starting with a proper gut health assessment, a nutrient panel, an honest look at stress and sleep, and a review of any chronic infections are the obvious first steps. These do not take the place of thyroxine if that is what your body needs, but they may lower your antibodies over time and sometimes lower your dosage too.
How a naturopath works alongside your GP or endocrinologist
Floralia's approach to thyroid care in pregnancy is collaborative. Your GP or endocrinologist will be responsible for the thyroid treatment and testing, while a Floralia naturopath will deal with the fundamentals of nutrition, digestion, and lifestyle factors.
This translates to: your endocrinologist fine-tunes your dosage of thyroxine, while your naturopath from Floralia examines all your nutrient levels, takes into account any digestive issues you have, considers your level of stress and sleeping habits, and creates an individualised approach towards those elements that do not fall under the umbrella of pharmacological management. Lab results are exchanged between both healthcare providers when appropriate. Nutrient selection takes into consideration your pregnancy status and thyroxine dosage.
The approach is well suited for women who are under medical care but want to have issues beyond that covered. It is also ideal for women who require a more detailed evaluation before conception than what they can get from a GP visit.
Postpartum thyroiditis and the months no one warns you about
Postpartum thyroiditis is estimated to occur in one out of every twenty women during the first year after delivery, especially in those who have either type 1 diabetes, a history of autoimmune thyroid disease, or TPO antibodies. In spite of being that common, it is often overlooked due to the fact that its symptoms are too similar to the typical insanity of becoming a new mother.
How to tell postpartum thyroiditis apart from postnatal depression
The hypothyroid phase of postpartum thyroiditis is characterised by fatigue, poor mood, mental confusion, water retention, hair loss, and sensitivity to cold. All these manifestations are also seen in postpartum depression, sleeplessness, changes in hormone levels due to lactation, or normal life as a new mum.
What sets it apart is that it appears in your blood test results. If you are experiencing symptoms between three and nine months post-birth and attributing it to your exhaustion as a new mother, then requesting a thyroid panel may be beneficial. A basic thyroid stimulating hormone (TSH), free thyroxine (T4) and antithyroid peroxidase antibodies (TPO) test will reveal if there is any thyroid factor involved in your symptoms. This is one of the most underused tests in postpartum care.
The biphasic pattern: hyperthyroid phase, then hypothyroid phase
The course of classic postpartum thyroiditis is usually two-phase. The first phase is hyperthyroidism and usually starts one to three months after delivery. This stage may persist for three months and involves symptoms like irritability, intolerance to heat, fatigue, tachycardia, and unexplained weight loss.
The hypothyroidism phase comes next, lasting for 12 months and even more. Symptoms include fatigue, weight gain, depression, and sensitivity to cold temperatures. Not all women go through these two stages. Sometimes, some women may go into the hypothyroidism stage without going through the hyperthyroidism phase. The pattern is variable enough that testing is the only reliable way to know what is happening.
Who is most likely to develop permanent hypothyroidism after birth
Hypothyroidism becomes a condition in 20% to 40% of women after postpartum thyroiditis. This is especially true in cases where patients have high levels of TSH in their system during postpartum thyroiditis, and in cases where the patient has very high levels of TPO antibodies. This is the reason why follow-up is important even after a year.
There is a strong possibility that you will develop postpartum thyroiditis if you have already been diagnosed with it during your first pregnancy. It is important that you know this before getting pregnant again so you can plan accordingly.
Thyroid medication and breastfeeding
Thyroxine is safe in breastfeeding since this is the natural hormone produced by your own body. Furthermore, the amount absorbed by breast milk is insignificant. Therefore, there is no cause for stopping thyroxine during nursing.
More caution is needed when using anti-thyroid medications. PTU and methimazole both get into the breast milk in low quantities; however, it is advisable that you discuss which drug and how much to take with your endocrinologist. In normal dosages, the two are deemed acceptable for use while breastfeeding.
Replenishing your thyroid after birth
Discussion on the management of the thyroid generally ends at the twelve-week check after birth. However, it is at this stage that many women are suffering, and a thoughtful intervention from naturopathy can make all the difference.
Why postpartum nutrient depletion hits the thyroid hard
Pregnancy and breastfeeding both use up the same nutrients the body needs for the proper functioning of the thyroid gland. The body’s levels of iron fall dramatically, especially if there has been any blood loss during childbirth. Iodine is provided in the breast milk to feed the baby, as is normal, although this means the mother has little left herself if she does not take in enough iodine.
The thyroid gland that functioned well before pregnancy will truly struggle after the delivery of the baby due to the reallocation of resources. This explains why many women feel “not themselves” for about twelve to eighteen months after childbirth, despite getting more sleep. Postpartum care in Perth can look at the full nutrient picture alongside thyroid markers rather than just TSH.
Iodine intake while breastfeeding
Iodine demands are still high when nursing (about 250 micrograms daily) since the child still depends on the mother's iodine levels to produce thyroid hormones. While most prenatal vitamins contain enough iodine to meet this demand, others do not, and there is a rapid decline in iodine intake after giving birth.
A breastfeeding-specific multivitamin, or alternatively an iodine supplement prescribed by an expert, makes perfect sense for most nursing mothers. Dosage needs to be tailored, especially for those with autoimmune thyroiditis, because iodine overdosage may cause an autoimmune flare-up.
Rebuilding for a second pregnancy
If you are preparing for your second child, then it is important to consider the interval in which the baby is conceived. The nutrients used up in the previous pregnancy and lactation period need time to be rebuilt before starting the next pregnancy cycle.
Preconception evaluation prior to pregnancy involves an assessment of your current nutritional status, your current thyroid state, any changes in TPO antibodies, and how modifications would make for a healthier pregnancy next time around. Women who go through this process tend to experience higher energy levels in their second pregnancy and easier postnatal recovery.
When to book a consultation with a naturopath at Floralia
It is uncommon for thyroid treatment during pregnancy to be a one-size-fits-all process. This is the main reason why Floralia chooses to tailor thyroid support specifically for you and does not follow any blanket guidelines. An initial consultation might be worthwhile if you are planning on conceiving and would like a pre-conception consultation, if you have already been diagnosed with a thyroid problem and require assistance with devising an appropriate course of action together with your GP/endocrinologist, if you have normal test results but are experiencing symptoms, or if you had previous miscarriages/recurrent losses.
Your appointments will involve your full medical history, analysis of any previous blood work that you have had done, further testing if necessary, and a personalised protocol based on your stage of pregnancy or pre-pregnancy journey. The idea is to collaborate with your doctors, not against them.
