Female Fertility Tests Explained: AMH, FSH, AFC and More

A fertility investigation generates a series of test results that can feel overwhelming without context. An AMH of 1.2 — is that good or bad? FSH of 12 — should I be worried? AFC of 8 — what does that mean for IVF? These questions are universal, and the confusion is understandable: medical reports rarely come with plain-language interpretations.

This guide explains the key female fertility tests — what each one measures, what the numbers mean in clinical practice, and how they are interpreted together. Because the most important thing to understand is that no single test number tells the full story: it is the combination of tests, interpreted in the context of your age and clinical picture, that gives an accurate and useful picture.

The Ovarian Reserve Tests

AMH — Anti-Mullerian Hormone

AMH is produced by the granulosa cells of small, early-stage follicles in the ovaries. Because these follicles are continuously present, AMH can be measured on any day of the menstrual cycle — a significant practical advantage.

AMH is the best available blood marker of ovarian reserve — reflecting the size of your remaining egg pool. The higher the AMH, the larger the pool. The lower the AMH, the smaller the pool.

Approximate reference ranges in Indian fertility practice:

• High (often PCOS): Above 4.0 ng/ml
• Normal: 1.5 to 4.0 ng/ml
• Low-normal: 1.0 to 1.5 ng/ml
• Low (diminished reserve): 0.5 to 1.0 ng/ml
• Very low: Below 0.5 ng/ml

Critical caveat: AMH measures quantity, not quality. A woman with low AMH can have excellent-quality eggs. A woman with high AMH (PCOS) can have quality concerns. AMH predicts how many eggs IVF stimulation is likely to retrieve — not whether those eggs will fertilise, develop into healthy embryos, or result in a pregnancy.

FSH — Follicle Stimulating Hormone

FSH is the pituitary hormone that drives follicle development. It is measured on day 2 or 3 of the menstrual cycle. A higher FSH indicates the pituitary is working harder to stimulate the ovaries — typically because ovarian reserve is declining and the feedback response is weaker.

Reference ranges for day 2 to 3 FSH:

• Normal: Below 10 mIU/ml
• Borderline: 10 to 15 mIU/ml
• Elevated (suggests reduced reserve): Above 15 mIU/ml
• Very elevated (suggests POI): Above 25 to 40 mIU/ml

FSH is more variable cycle-to-cycle than AMH. A single elevated reading should be interpreted cautiously — repeat testing is appropriate before drawing firm conclusions. AMH is generally the more reliable single marker.

LH — Luteinising Hormone

LH is measured alongside FSH on day 2 to 3. An LH-to-FSH ratio above 2:1 or 3:1 suggests PCOS. LH is also the hormone that triggers ovulation — its surge (detected on urine LH kits or blood tests) is used to time intercourse or IUI. Outside of PCOS assessment and ovulation tracking, isolated LH measurement adds limited diagnostic value.

Oestradiol (E2)

Day 2 to 3 oestradiol provides context to FSH. Elevated early-cycle oestradiol (above 60 to 80 pg/ml) can artificially suppress FSH — making a borderline FSH appear normal. A "normal" FSH with elevated oestradiol is a warning sign. Oestradiol is also the key hormone monitored throughout IVF stimulation to track follicle development.

AFC — Antral Follicle Count

The AFC is performed by transvaginal ultrasound on day 2 to 5 of the cycle. The embryologist or sonographer counts the number of small, resting follicles (typically 2 to 10 mm) in both ovaries combined. Each antral follicle represents a potentially recruitable egg in that stimulation cycle.

AFC reference ranges:

• Good reserve (high response expected): AFC above 15 to 20
• Normal: AFC 10 to 15
• Low-normal: AFC 6 to 10
• Poor reserve (low response expected): AFC below 6

AFC is the best short-term predictor of IVF stimulation response — arguably more directly useful than AMH for planning a specific cycle. AMH and AFC together provide a comprehensive picture of reserve status.

Additional Hormonal Tests

Prolactin

Elevated prolactin (hyperprolactinaemia) outside of pregnancy and breastfeeding suppresses the hormonal cascade driving ovulation, causing irregular or absent periods and infertility. Common causes include a small benign pituitary tumour (prolactinoma) and certain medications. Highly treatable with cabergoline.

TSH — Thyroid Stimulating Hormone

TSH screens for thyroid disease. Both hypothyroidism and hyperthyroidism impair ovulation and increase miscarriage risk. Thyroid disorders are common in Indian women — TSH is standard in all fertility workups. In the fertility context, TSH should ideally be below 2.5 mIU/L before conception attempts.

Fasting Glucose and Insulin (HOMA-IR)

Particularly important when PCOS is suspected. Insulin resistance is the central metabolic feature of most PCOS cases and drives many of its hormonal abnormalities. The HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) index calculated from fasting glucose and insulin identifies insulin resistance that may not yet have produced elevated fasting glucose.

Putting It All Together

Fertility test results should never be interpreted in isolation. A comprehensive picture requires the combination of AMH, FSH, LH, oestradiol, AFC, prolactin, TSH, and clinical history. For example:

• Low AMH + elevated FSH + low AFC: Consistent and strong evidence of diminished reserve — act promptly.
• Low AMH + normal FSH + normal AFC: Mixed picture — may reflect a technical variation or early reserve decline; repeat recommended.
• High AMH + elevated LH:FSH ratio + polycystic ovaries on ultrasound: Classic PCOS pattern.
• Normal AMH + elevated prolactin: Ovulatory disorder from hyperprolactinaemia — highly treatable.

The goal of this combination of tests is not to assign a number but to understand the reproductive biology of the individual woman — and then to plan the most appropriate treatment.

Frequently Asked Questions

Q1. On which day of my cycle should I have these tests done?

AMH can be done on any cycle day. FSH, LH, and oestradiol should be done on day 2 or 3 of a natural cycle (day 1 being the first day of proper menstrual flow). AFC ultrasound is ideally performed on day 2 to 5. TSH, prolactin, fasting glucose, and insulin can be done on any day, though fasting tests require an overnight fast.

Q2. My AMH and FSH are both normal. Does this guarantee normal fertility?

Normal reserve tests improve the probability of a good IVF response and suggest the egg pool is adequate — but they do not guarantee fertility. Egg quality, tubal patency, uterine structure, and male factors are all independent of AMH and FSH. A complete fertility investigation is necessary even when ovarian reserve markers are reassuring.

Q3. How often should fertility tests be repeated?

As a general guide, AMH and AFC results older than 6 to 12 months should be repeated before making major treatment decisions — reserve does change over time, and an up-to-date picture is important. FSH and oestradiol results should be fresh (within the last 1 to 2 cycles) before starting any fertility treatment.