Women's Hormonal Health — PCOS, Fertility & the Menstrual Cycle

GnRH: (from hypothalamus) → stimulates pituitary to release **FSH + LH** → which signal ovaries to produce **oestrogen + progesterone**.

FSH (Follicle-Stimulating Hormone):: Drives follicle development in the ovaries. Tested on Day 2–3 of cycle. High FSH suggests poor ovarian reserve or menopause approaching. Normal: 3–10 mIU/mL (follicular phase).

LH (Luteinising Hormone):: Triggers ovulation. High LH:FSH ratio (>2:1) on Day 2–3 is a hallmark of PCOS. LH surges ~24–36 hours before ovulation — tracked in fertility planning.

Estradiol (E2):: Primary oestrogen. Low levels cause bone loss and hot flashes. High levels (unexplained) can indicate ovarian cysts or tumours.

Progesterone:: Tested on Day 21 to confirm ovulation occurred. Low mid-luteal progesterone indicates anovulatory cycles — a common cause of infertility.

AMH (Anti-Müllerian Hormone):: Best measure of ovarian reserve — the number of eggs remaining. Can be tested on any cycle day. Declining AMH predicts reduced fertility years before menopause. Low AMH + high FSH = poor reserve.

Prolactin:: Elevated prolactin suppresses ovulation and causes irregular periods. Can be caused by stress, certain medications, or a pituitary tumour (prolactinoma).

DHEA-S & Testosterone:: When elevated in women, these androgens indicate hyperandrogenism — a core feature of PCOS — causing acne, excess hair, and hair loss.

Polycystic Ovary Syndrome (PCOS): affects approximately 1 in 5 Indian women of reproductive age — and the majority are undiagnosed. PCOS is not simply a 'cyst problem'; it is a complex metabolic and endocrine condition.

Rotterdam Criteria (2 of 3 needed for diagnosis)::

• Irregular or absent periods

• Signs of hyperandrogenism (excess androgens in blood or symptoms like acne, hirsutism)

• Polycystic-appearing ovaries on ultrasound

Hormonal pattern in PCOS::

• High LH, normal or low FSH (elevated LH:FSH ratio)

• Elevated testosterone and/or DHEA-S

• Often insulin resistant (fasting insulin + HOMA-IR important to check)

• AMH typically very high (many follicles = many eggs, but ovulation is irregular)

Associated risks:: PCOS significantly raises the risk of Type 2 diabetes, cardiovascular disease, endometrial cancer, and pregnancy complications. Lifestyle management (diet, exercise) is the first-line treatment.

Hormonal markers of menopause::

• FSH > 30–40 mIU/mL (consistently high)

• AMH < 0.1 ng/mL (near-zero)

• Low estradiol

Always pair with thyroid testing:: Hypothyroidism and PCOS frequently coexist and share symptoms (fatigue, weight gain, irregular periods, hair loss). A combined hormonal + thyroid panel gives the full picture.

• Women with irregular, missed, or painful periods

• Anyone with PCOS symptoms: acne, excess facial/body hair, weight gain, hair thinning

• Couples planning pregnancy (baseline hormonal assessment)

• Women over 35 or those wanting to understand their fertility window

• Anyone experiencing unexplained fatigue, mood swings, or hot flashes

• Women with recurrent miscarriage (progesterone, thyroid, and clotting markers)

• Annual hormonal screen recommended from age 35+