Blood Tests on Menopause Hormone Therapy (HRT)
What to monitor on oestrogen patches, gels, and progesterone — Australian reference ranges, a clear monitoring schedule, and the red flags that need urgent attention.
The Quick Answer
Menopause hormone therapy (MHT, also called HRT) is the most effective treatment for menopausal symptoms — hot flushes, night sweats, sleep disruption, vaginal dryness, and mood changes. It also protects bones and cardiovascular health when started before age 60 or within 10 years of menopause. HRT prescriptions in Australia have risen sharply since the evidence base was re-evaluated in the 2010s, and now more than 500,000 Australian women use it.
Blood tests are used to confirm the oestrogen dose is adequate (oestradiol level), exclude conditions that mimic menopause (especially thyroid disease), and monitor long-term cardiovascular and liver safety. The good news: modern body-identical transdermal HRT has a much safer blood test profile than the older oral preparations that drove much of the early safety concern.
How HRT Affects Your Blood Tests
Oestrogen has receptors throughout the body — in the brain, bones, blood vessels, liver, skin, and urogenital tract. Replacing oestrogen after menopause reverses many of the changes that occur in its absence. In blood tests, you will typically see: rising oestradiol, falling FSH (confirming adequate oestrogen replacement), improving HDL cholesterol, and in women with pre-existing insulin resistance, improving HbA1c.
The key difference between oral and transdermal oestrogen is the liver. Oral oestrogen is absorbed from the gut and goes directly to the liver (first-pass metabolism), where it stimulates production of clotting factors, SHBG, and triglycerides. Transdermal oestrogen (patches, gels, sprays) absorbs through the skin into the bloodstream, bypassing the liver entirely. This is why transdermal preparations have a much more favourable blood test and safety profile.
Progesterone or progestogen is added for any woman who has not had a hysterectomy, to protect the uterine lining from oestrogen-driven overgrowth. Body-identical micronised progesterone (Prometrium) has a better safety and side-effect profile than older synthetic progestogens.
Key Blood Tests to Monitor on HRT
Reference ranges from RCPA guidelines and Australian Menopause Society recommendations. Therapeutic targets on HRT differ from general population ranges.
Oestradiol (E2)
Confirm absorption and adequate circulating levels. Below 150 pmol/L on standard doses suggests poor absorption or compliance issues. Above 800 pmol/L suggests dose too high. Test patches on day 3-4 after application; gels first thing in the morning before applying the next dose. Note: results vary significantly between labs and assay methods.
FSH (follicle-stimulating hormone)
Confirm adequate oestrogen and monitor menopausal status. FSH falls as oestradiol rises. A suppressed FSH on HRT confirms the oestrogen dose is physiologically significant. In perimenopause, FSH fluctuates considerably cycle-to-cycle, so a single normal FSH does NOT rule out perimenopause.
LH (luteinising hormone)
Complement to FSH for menopausal status assessment. Less commonly used than FSH alone for monitoring. Useful at baseline to confirm menopausal status before starting HRT, especially in women who have had a hysterectomy and cannot use cycle-based FSH interpretation.
TSH (thyroid stimulating hormone)
Exclude thyroid disease, which mimics menopause symptoms. Fatigue, mood changes, weight gain, sleep disruption, and brain fog are shared by hypothyroidism and menopause. Always check TSH before starting HRT and annually thereafter. Women on levothyroxine may need a dose increase when starting oestrogen, as oestrogen raises thyroid-binding globulin.
Lipid panel (total cholesterol, LDL, HDL, triglycerides)
Oestrogen improves lipids; oral HRT can raise triglycerides. Transdermal oestrogen generally improves the lipid profile without raising triglycerides. Oral oestrogen tablets raise triglycerides in some women. Annual lipid monitoring confirms the cardiovascular benefit of treatment.
HbA1c
Oestrogen improves insulin sensitivity; screen for diabetes. Menopause is associated with worsening insulin resistance and increased type 2 diabetes risk. HRT, particularly transdermal, may improve insulin sensitivity. Annual HbA1c is good practice for women in the perimenopausal and menopausal age group.
LFTs (ALT, AST, GGT, bilirubin)
Oral oestrogen is metabolised by the liver and can affect LFTs. Oral HRT has a higher liver burden than transdermal preparations due to first-pass hepatic metabolism. LFTs should be checked at baseline and at 3 months on oral preparations, then annually. Women with pre-existing liver disease should use transdermal HRT.
Full blood count (FBC)
Screen for anaemia from heavy perimenopause bleeding. Heavy irregular bleeding is common in perimenopause and can lead to iron deficiency anaemia before HRT stabilises cycles. FBC with ferritin is important if periods are heavy or irregular before starting HRT. Ferritin below 30 mcg/L indicates iron deficiency even with a normal haemoglobin.
Vitamin D (25-hydroxyvitamin D)
Essential for bone protection alongside oestrogen. Oestrogen and vitamin D work together to protect bone density in menopause. Many Australian women remain vitamin D deficient despite our sunshine. Annual testing and supplementation to achieve above 75 nmol/L optimises bone protection alongside HRT.
SHBG (sex hormone binding globulin)
Affects free oestradiol and testosterone availability. Oral oestrogen raises SHBG, which can bind testosterone and reduce libido. Transdermal oestrogen has a neutral or lower effect on SHBG. If libido does not improve on HRT, check SHBG and free/total testosterone — testosterone therapy is available for women in Australia.
Side Effects and Their Blood Test Connections
Most side effects of HRT are dose-related or formulation-related and can be managed by adjusting the prescription. Understanding the blood test correlates helps you work with your doctor to optimise your therapy.
Breast tenderness
Common in the first 3 months, particularly with higher oestrogen doses. Usually settles. Persistent or worsening breast tenderness with an oestradiol above 600 pmol/L suggests the dose should be reduced. Annual mammogram continues as usual on HRT.
Bloating and fluid retention
Often caused by oestrogen dominance relative to progesterone. Check oestradiol level — if above 600 pmol/L, dose reduction helps. Switching from oral to transdermal preparations can also reduce bloating. Ensure adequate progesterone is prescribed.
Headaches and migraines
Fluctuating oestrogen levels (especially on patches changed every 3-4 days) can trigger migraines. Continuous delivery via daily gel or a 7-day patch can reduce fluctuation. Women with migraine with aura should use transdermal oestrogen rather than oral, as oral preparations may increase stroke risk in this group.
Breakthrough or irregular bleeding
Expected in perimenopause and in the first 3-6 months on continuous combined HRT. Persistent bleeding beyond 6 months, heavy bleeding, or bleeding after a period of amenorrhoea warrants a pelvic ultrasound (to measure endometrial thickness) and possible endometrial biopsy. Adequate progesterone is essential for endometrial protection.
Mood changes or anxiety
Can indicate low oestradiol (check level if symptoms persist), inadequate progesterone, or low testosterone. Micronised progesterone (Prometrium) has a better mood profile than synthetic progestogens for many women. If mood does not improve on oestrogen alone, discuss testosterone with your GP.
DVT symptoms — leg pain and swelling
Oral oestrogen increases clotting factor production in the liver and raises DVT risk 2-3 fold. Transdermal oestrogen does NOT carry this risk. If you have leg pain, swelling, or redness in one calf, seek same-day medical review for Doppler ultrasound and D-dimer. This is a medical emergency if a clot is confirmed.
Red Flags — When to Seek Urgent Help
These symptoms require same-day or emergency review — do not wait for your next scheduled appointment:
Leg pain, calf swelling, or redness (DVT signs)
Deep vein thrombosis is a rare but serious risk primarily with oral oestrogen. Seek same-day emergency review for ultrasound Doppler and D-dimer. Do not ignore unilateral calf swelling or pain.
Sudden chest pain or shortness of breath
May indicate pulmonary embolism from a dislodged DVT. Call 000 immediately. This is more relevant for women on oral oestrogen, but all women on HRT should know this red flag.
Severe or new-pattern headaches
A headache that is the worst of your life, thunderclap onset, or associated with visual changes or one-sided weakness could indicate haemorrhagic stroke. Call 000 immediately. Women with migraine with aura should discuss stroke risk with their GP before starting any oestrogen-containing HRT.
Persistent irregular or heavy bleeding
Breakthrough bleeding beyond 6 months on continuous combined HRT, or any postmenopausal bleeding in a woman who has been amenorrhoeic for 12 or more months, requires endometrial ultrasound to exclude endometrial hyperplasia or cancer.
New breast lump
Report any new breast lump, nipple discharge, skin dimpling, or nipple inversion to your GP urgently regardless of HRT status. Annual mammogram continues as usual on HRT. A new lump warrants triple assessment (mammogram, ultrasound, biopsy if indicated).
Severe abdominal pain, jaundice, or dark urine
Oral oestrogen can rarely cause gallstones or liver problems. Jaundice (yellow tinge to eyes or skin), right upper abdominal pain, and dark urine warrant urgent LFTs, bilirubin, and abdominal ultrasound.
HRT Monitoring Schedule
Based on Australian Menopause Society and RANZCOG guidelines for menopause hormone therapy monitoring.
Baseline before starting HRT
Oestradiol, FSH, LH, TSH, full blood count, ferritin (if heavy periods), lipid panel, HbA1c, LFTs, vitamin D, blood pressure. This establishes your hormonal status and identifies contraindications before prescribing.
Three months after starting or changing dose
Oestradiol level (to confirm absorption and adequate levels), TSH (if on levothyroxine — may need dose adjustment). Symptom review: are hot flushes, sleep, and mood improving? If oestradiol is below 200 pmol/L and symptoms persist, dose may need to increase.
Six months (if any dose adjustment at 3 months)
Repeat oestradiol after any dose change to confirm you are now in the therapeutic range. Review bleeding pattern on combined HRT — irregular bleeding beyond 6 months warrants endometrial ultrasound.
Annual comprehensive review
Full panel: oestradiol, FSH, TSH, lipid panel, HbA1c, LFTs, FBC, vitamin D, blood pressure. Plus clinical breast examination and mammogram reminder. Review ongoing indication for HRT and benefit-risk balance annually.
After any significant health change
New cardiovascular event, stroke, DVT, or new breast cancer diagnosis requires immediate HRT review with your GP or specialist. Some conditions are absolute contraindications to continued HRT.
If thyroid replacement dose needs adjusting
Starting oestrogen raises thyroid-binding globulin and can increase levothyroxine requirements. Recheck TSH 6-8 weeks after starting HRT if you take levothyroxine. Women often need a 25 mcg dose increase at this time.
Bone density (DEXA scan)
A DEXA scan is recommended at menopause baseline for women with risk factors (family history of osteoporosis, low body weight, previous fracture, smoking, or early menopause before 45). Repeat every 2-5 years on HRT to confirm bone density is being maintained.
Lifestyle and Formulation Choices That Affect Your Results
Transdermal over oral oestrogen
Safety preferencePatches, gels (Estrogel, Sandrena), and sprays (Lenzetto) bypass the liver's first-pass metabolism, avoiding the increase in clotting factors and triglycerides that oral tablets cause. Australian menopause specialists now strongly favour transdermal for most women, especially those with cardiovascular risk factors.
Micronised progesterone (Prometrium)
Progesterone choiceBody-identical micronised progesterone has a better safety profile than older synthetic progestogens (norethisterone, MPA) for breast tissue, cardiovascular risk, and mood. Available in Australia as Prometrium 100mg and 200mg capsules. Can be used vaginally for women who dislike oral side effects.
Weight-bearing and resistance exercise
Bone healthOestrogen and mechanical loading work synergistically to maintain bone density. Walking, dancing, running, and resistance training (weights or resistance bands) all stimulate bone formation. Aim for at least 30 minutes of weight-bearing activity most days.
Calcium-rich diet
Bone healthDairy, fortified plant milks, canned sardines with bones, almonds, and leafy greens provide dietary calcium to support bone protection alongside HRT and vitamin D. Aim for 1000-1300 mg of calcium from food per day (not supplements, which carry cardiovascular concerns at high doses).
Limit alcohol to below NHMRC guidelines
Cancer riskAlcohol increases circulating oestradiol levels and independently increases breast cancer risk. The combination of HRT and high alcohol intake raises breast cancer risk more than either alone. Staying below 10 standard drinks per week minimises this interaction.
Quit smoking
Cardiovascular safetySmoking increases the risk of blood clots and cardiovascular disease, which is additive to any residual risk from oral HRT. Smoking also accelerates bone loss. If you smoke, TGA-approved nicotine replacement and Quitline (13 7848) can help you stop.
Annual mammogram and cervical screening
SurveillanceBreastScreen Australia invites women aged 40-74 for free mammograms every 2 years. HRT (particularly combined oestrogen-progesterone) modestly increases breast density and breast cancer risk after 5 years of use. Adhering to screening is the most important safety measure on long-term HRT.
Related Reading
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This page provides general educational information about blood test monitoring for menopause hormone therapy. It is not a substitute for professional medical advice. HRT decisions are highly individual and depend on your personal health history, risk factors, and preferences. Always discuss your monitoring plan with your GP or menopause specialist. SmarterBlood does not provide medical care.