Fertility Blood Tests for Women: AMH, FSH, LH, and What They Mean

Quick answer

A female fertility blood panel checks AMH, day-3 FSH and LH, day-3 estradiol, prolactin, thyroid hormones, and day-21 progesterone. AMH is the best single marker of how many eggs you have left. You can test AMH on any day. FSH, LH, and estradiol need a day-3 blood draw for an accurate reading.

The female fertility blood panel

AMH: your egg supply marker

Your AMH is short for anti-Müllerian hormone. It comes from the small egg follicles in your ovaries. Think of it like a fuel gauge. It shows roughly how many eggs you have left. It does not show how healthy each egg is.

You can test AMH on any day of your cycle. The level barely moves week to week.

AMH drops as you age. Doctors compare your number to other women your age.

What your number can mean:

• Higher AMH for your age often means more eggs left.
• Lower AMH for your age often means fewer eggs left.
• Very low AMH, under 0.5, may mean a smaller egg supply. Talk to a fertility doctor.
• Very high AMH, over 4.0, often points to PCOS (polycystic ovary syndrome).

One key point. AMH predicts how you might respond to fertility treatment. It does not reliably predict natural pregnancy. Many women with low AMH still conceive. Some women with normal AMH still struggle.

Day-3 FSH: how hard your brain pushes your ovaries

FSH stands for follicle-stimulating hormone. It comes from your brain. It tells your ovaries to grow an egg each month. The normal range on day 3 is 3 to 10 IU/L.

• Under 10: normal ovarian reserve.
• 10 to 15: reduced ovarian reserve.
• Over 15: reserve is significantly reduced.

Think of FSH like a volume knob. As your egg supply drops, your brain turns up the volume. A rising day-3 FSH can be an early sign. It can mean perimenopause is getting closer.

Day-3 LH: the hormone that triggers ovulation

LH stands for luteinizing hormone. It works with FSH to trigger ovulation. The normal day-3 range is 2 to 10 IU/L.

Doctors also compare LH to FSH:

• A ratio under 1.5 is normal.
• A ratio over 2 to 1 is a classic PCOS sign.

Day-3 estradiol: a check on your FSH number

Estradiol is a form of estrogen. The normal day-3 range is 30 to 80 pg/mL.

A high day-3 estradiol can be a warning sign. It can hide a low ovarian reserve. Your brain works harder to get a response. That extra push shows up as higher estradiol. Always read estradiol together with FSH.

Day-21 progesterone: did you ovulate?

Progesterone rises after you ovulate. A level over 10 ng/mL on day 21 confirms ovulation for that month. This applies to a typical 28-day cycle.

Prolactin: a hormone that can quietly block ovulation

Normal prolactin sits under 25 ng/mL. A high level can stop ovulation. This is a common, fixable cause of fertility trouble.

Thyroid hormones: TSH and Free T4

Your thyroid runs your metabolism. It also shapes your fertility. For women planning pregnancy, doctors like TSH under 2.5 mIU/L. That is tighter than the usual adult target.

An untreated underactive thyroid can affect ovulation and pregnancy. Read more on how your TSH level affects your ability to conceive.

Other markers worth knowing

• Testosterone and SHBG help explain PCOS.
• DHEA-S is a hormone from your adrenal glands.
• 17-OH progesterone rules out a rare adrenal condition.
• TPO antibodies check for autoimmune thyroid disease.
• Vitamin D, B12, folate, and ferritin are nutrients your body needs for pregnancy.

When to time your fertility blood test

Timing matters if your cycles are regular.

• Day 3 (early in your cycle): AMH, FSH, LH, estradiol, prolactin, TSH, and thyroid antibodies. This is the best day to test.
• Day 21 (about a week before your period): progesterone confirms ovulation.
• Any day: AMH, prolactin, and TSH stay steady.

Timing gets trickier with irregular cycles or perimenopause. Your doctor may want more than one cycle.

If you use hormonal birth control, results are harder to read. Most workups need 2 to 3 cycles off birth control first.

Want to see how fertility hormones fit into your wider cycle health? A hormone panel for women also checks estrogen and progesterone.

Common patterns and what they suggest

Pattern 1: Normal reserve, regular ovulation

AMH is normal for your age. Day-3 FSH is under 10. Estradiol is under 80. Day-21 progesterone is over 10. This pattern usually means you can keep trying. If nothing happens after 6 to 12 months, ask a doctor for more tests.

Pattern 2: Diminished ovarian reserve

AMH is low for your age, often under 1.0. Day-3 FSH is high, often over 10. This pattern calls for a fertility specialist visit soon.

Pattern 3: PCOS pattern

AMH is often high, over 4.0. The day-3 LH to FSH ratio is over 2 to 1. Testosterone or DHEA-S may be high. Cycles are often irregular. This points toward PCOS-focused care.

Pattern 4: Low ovulation from stress or low weight

Estradiol is low. FSH and LH are low. Progesterone stays low since ovulation is not happening. This often follows low weight, heavy exercise, or high stress. It tends to improve once weight and rest are restored.

Pattern 5: High prolactin

Prolactin is high, often over 30. FSH and LH are low. Cycles are irregular or absent. The cause is often a medicine or a small, usually harmless pituitary growth. A doctor can find the cause and treat it.

Pattern 6: Perimenopause approaching

Day-3 FSH is rising. AMH is falling. Estradiol swings up and down. Cycles become less predictable. Talk to a specialist about your fertility timeline.

More than blood: the full fertility picture

Blood tests are the start, not the whole story. A full fertility check-up often adds more tests.

• Pelvic ultrasound counts visible follicles and checks for cysts or fibroids.
• Hysterosalpingogram (HSG) is an X-ray test. It checks if your fallopian tubes are open.
• Partner semen analysis matters too, since male factors cause many fertility issues.
• Genetic carrier screening is useful before you try to conceive.
• A lifestyle review covers weight, exercise, alcohol, smoking, and stress.

See what a full &you Labs panel covers if you want fertility hormones checked with your other health markers.

How to support your fertility through your biomarkers

A few changes can help your numbers if you plan a pregnancy.

• Folate: aim for 400 to 800 micrograms a day before you try.
• Vitamin D: fix a low level if you have one.
• B12 and ferritin: keep your stores healthy.
• Thyroid: aim for TSH under 2.5.
• Blood sugar: address prediabetes early.
• Weight: both very low and very high weight can affect fertility.
• Iodine: get enough, since it supports your baby's brain.

These changes usually take 3 to 6 months to show up. Plan ahead when you can.

When to see a fertility specialist

• Under 35: after 12 months of trying with no pregnancy.
• 35 to 40: after 6 months.
• Over 40: sooner, often after 3 months.
• Any age: sooner with PCOS, endometriosis, past pelvic surgery, or irregular cycles.

Frequently asked questions

When should I get fertility tested?

Good times to test are before you start trying, in your late 20s or early 30s for a baseline, or after 6 to 12 months without success. Test sooner with known risk factors.

Is AMH accurate?

AMH is the best single blood marker of ovarian reserve. It closely tracks how you respond to fertility treatment. It does not perfectly predict natural pregnancy, so doctors pair it with other tests.

Can AMH be improved?

AMH mostly reflects your ovarian reserve. Reserve declines with age and does not change much with lifestyle. Fixing a vitamin D deficiency may help slightly. The effect is small.

Are at-home fertility tests accurate?

Yes. A blood draw at home that goes to an accredited lab gives the same result as one done in a clinic. The accuracy comes from the lab test, not the location.

Should male partners also test?

Yes. Male factors cause 30 to 40% of infertility cases. A male fertility blood test alongside a semen analysis is a smart next step.

Key takeaways

• A female fertility panel checks AMH (any day), day-3 FSH, LH, and estradiol, day-21 progesterone, thyroid, and key nutrients.
• AMH is the strongest single marker of ovarian reserve.
• AMH does not perfectly predict natural pregnancy.
• Common patterns include low reserve, PCOS, low ovulation, high prolactin, and approaching perimenopause.
• Fixing folate, vitamin D, thyroid, and weight before pregnancy can help your odds.
• Blood tests are the start. Imaging and a partner's semen analysis complete the picture.