Hormone Levels During Your Menstrual Cycle: Oestrogen, Progesterone, LH & FSH

• A normal cycle runs 21–35 days, not just 28 — most variation comes from the first (follicular) half, while the luteal phase stays close to 14 days.
• Oestrogen dominates the first half (builds the lining, lifts mood and energy); progesterone dominates the second half (prepares for implantation, causes PMS-type symptoms).
• FSH grows the follicles; a mid-cycle LH surge triggers ovulation 24–36 hours later — this surge is what ovulation kits detect.
• Most hormone tests are timed: FSH/LH/oestradiol on cycle day 2–4, progesterone around day 21 (7 days before the next period).
• Stress, body weight, over-exercise, poor sleep and thyroid or iron problems can all disrupt these hormones and your cycle.
• See a doctor for cycles outside 21–35 days, missed periods, very heavy bleeding, or trouble conceiving after timed effort.

The textbook 28-day cycle is divided into four phases, but a normal cycle is anywhere from 21 to 35 days. Most of that variation comes from the first half of the cycle; the second half stays remarkably fixed at about 14 days. Counting always starts on day one of full bleeding, not spotting.

Menstrual phase (about days 1–5). This is your period. The lining built up in the previous cycle sheds because progesterone and oestrogen have dropped, triggering prostaglandins and narrowing of the lining's blood vessels. All four hormones are at their lowest: oestrogen around 20–50 pg/mL, progesterone under 1 ng/mL, with FSH just beginning to rise.

Follicular phase (about days 6–13). The rebuilding phase. FSH from the pituitary stimulates several ovarian follicles, and usually one dominant follicle is selected by around day 7–10 while the rest fade. The growing follicle pumps out oestrogen (peaking near 200–400 pg/mL), which rebuilds the womb lining and brings the mid-cycle lift in energy, mood and libido many women notice. Cervical mucus becomes clear and stretchy like egg white — one of the natural fertility signs. To learn how to read it, see understanding cervical mucus.

Ovulatory phase (around day 14). High oestrogen flips the brain's feedback from negative to positive and triggers a sharp LH surge, which releases the egg 24–36 hours later. The egg survives about 12–24 hours; sperm can survive up to five days, so the fertile window runs from about five days before ovulation to one day after. Some women feel a brief one-sided ache called mittelschmerz, or ovulation pain. For the bigger picture, see what ovulation actually means.

Luteal phase (about days 15–28). The empty follicle becomes the corpus luteum and produces high progesterone (alongside oestrogen), turning the lining into a soft, receptive bed for a possible embryo. This phase is fixed at 14 ± 2 days because the corpus luteum has a set lifespan. If no pregnancy occurs, it breaks down, progesterone and oestrogen fall, and the next period begins. A short or weak luteal phase can affect conception — see luteal phase defect.

Oestrogen rules the first half of the cycle. It grows the follicle, rebuilds the lining, and drives the mid-cycle improvement in mood, energy and libido. Your body makes three main oestrogens — oestradiol (E2, the main one in your reproductive years), oestrone (E1, dominant after menopause) and oestriol (E3, dominant in pregnancy). Oestradiol is the one that matters most for the cycle, made mainly by the growing follicle, then by the corpus luteum after ovulation.

Oestradiol follows a clear pattern: low (20–50 pg/mL) during your period, climbing through the follicular phase to a peak of 200–400 pg/mL just before ovulation, dipping briefly, then rising to a second smaller peak (150–300 pg/mL) in the mid-luteal phase before falling at cycle's end. That pre-ovulation peak is what sets off the LH surge.

Oestrogen's reach goes far beyond reproduction. Receptors sit in the brain, bones, heart and blood vessels, skin, breasts and metabolic organs. It supports mood and memory (through serotonin and dopamine), protects bone density, helps cardiovascular and vaginal tissue health, and influences how your body handles insulin. Many of the changes across the cycle — and at What Is Perimenopause? Navigating the Transition with Confidence, when oestrogen becomes erratic — reflect these wide-ranging effects.

In the clinic, oestradiol is usually measured on cycle day 2–4 (early follicular phase) to check baseline ovarian function; the normal range there is 20–50 pg/mL. Mid-cycle and luteal testing is rarely useful because levels swing so fast. At Indian labs, oestradiol costs roughly ₹600–1,000 and is part of any infertility or missed-period workup.

Progesterone rules the second half of the cycle. It transforms the lining so an embryo can implant, supports an early pregnancy if it happens, and produces the familiar pre-period symptoms — bloating, breast tenderness, mood shifts and food cravings. It comes almost entirely from the corpus luteum, which only forms after ovulation. This is the key point: meaningful progesterone in the second half proves you ovulated. Cycles without ovulation stay low in progesterone throughout — see how to detect anovulatory cycles.

Progesterone is under 1 ng/mL through your period and the follicular phase. After ovulation it rises fast, peaking at 5–20 ng/mL around cycle day 21–23 (mid-luteal phase) — the ideal moment to confirm ovulation with a blood test (a level above 3–5 ng/mL confirms it happened). If pregnancy occurs, hCG from the embryo keeps the corpus luteum producing progesterone for about ten weeks until the placenta takes over. If not, the corpus luteum dissolves within 14 ± 2 days, progesterone drops sharply, and your period starts.

Progesterone's effects explain most luteal-phase symptoms: it makes the lining secretory and ready for implantation, stimulates breast tissue (tenderness), raises basal body temperature by 0.3–0.6°C, causes mild fluid retention (bloating), relaxes smooth muscle (constipation), and acts on GABA in the brain. That GABA effect is calming for some women but mood-lowering or anxiety-provoking for others, which is part of why luteal mood ranges from mild dips to severe premenstrual dysphoric disorder (PMDD).

Clinically, a mid-luteal progesterone (day 21 of a 28-day cycle, or about 7 days before your expected period, adjusted for your own cycle length) is the standard way to confirm ovulation. At Indian labs it costs about ₹600–1,000. Progesterone supplements (oral, vaginal or injection) are used for luteal support in fertility treatment, for lining protection in PCOS or anovulatory cycles, and to bring on a withdrawal bleed when periods are absent.

LH and FSH are the two pituitary hormones that run your ovaries. They are released in pulses, driven by gonadotropin-releasing hormone (GnRH) from the hypothalamus in a tightly timed loop. Both shift in characteristic ways across the cycle, and those patterns are useful for diagnosis.

FSH drives early follicle growth. It rises from a baseline of about 3–10 mIU/L during the late luteal and early menstrual phases — the falling oestrogen and progesterone at the end of the previous cycle release the brakes on the pituitary. Rising FSH wakes up several follicles, but as the dominant one grows and makes more oestrogen, that oestrogen feeds back to push FSH down again. So FSH actually dips in the mid-follicular phase, has a small bump at mid-cycle, then stays low through the luteal phase.

LH is the ovulation trigger. It stays low (about 2–10 mIU/L) for most of the follicular phase. When oestrogen peaks at mid-cycle, feedback flips from negative to positive — a feature unique to the female reproductive axis — and the pituitary fires a large LH surge of 50–100 mIU/L. The surge lasts roughly 24–48 hours and releases the egg 24–36 hours after it begins. Afterwards LH falls back to baseline; the corpus luteum sustains itself for the rest of the luteal phase.

Because LH spills into urine soon after release, ovulation predictor kits can detect the surge. Brands sold across India (i-Know, Velocit, Clearblue) cost roughly ₹150–700 a pack; you test daily from about cycle day 10 until you get a positive, then expect ovulation in 24–36 hours. They are useful for timing intercourse when trying to conceive, but less reliable for avoiding pregnancy than dedicated contraception. In the clinic, FSH and LH are measured on cycle day 2–4: high FSH (above ~10–15 mIU/L) suggests low ovarian reserve, a high LH-to-FSH ratio (above 2:1) points toward PCOS, and low FSH and LH together point to a hypothalamic or pituitary cause. Together they cost about ₹800–1,500 at Indian labs.

The cycle is one of the body's most elegant feedback systems, with looping signals between the hypothalamus, pituitary and ovaries. Understanding it helps you read test results and see why so many conditions disrupt periods. The hypothalamus releases GnRH in pulses every 60–90 minutes (faster in the follicular phase, slower in the luteal phase). GnRH tells the pituitary to release LH and FSH, which tell the ovaries to grow follicles and make oestrogen and progesterone.

Negative feedback runs most of the cycle: oestrogen and progesterone from the ovaries quiet GnRH, LH and FSH, keeping levels controlled. This is also how the combined pill works — its synthetic hormones mimic luteal-phase levels and suppress LH and FSH, so no follicle matures and no ovulation happens. For periods specifically, see using the pill to regulate periods.

Positive feedback is the brief mid-cycle exception. When oestrogen stays above a threshold (around 200 pg/mL for 36–48 hours), the feedback flips and produces the LH surge that triggers ovulation. When this flip fails — as in PCOS or hypothalamic dysfunction — ovulation doesn't happen, leading to anovulatory cycles, irregular periods and difficulty conceiving.

Other regulators fine-tune the system: kisspeptin (an upstream switch for GnRH), inhibin and activin (which modulate FSH), and anti-Müllerian hormone (AMH, a marker of egg reserve). Stress hormones such as cortisol suppress GnRH and can stall the whole cycle. Because the axis is also linked to insulin, leptin and thyroid hormone, conditions like PCOS, thyroid disease, eating disorders and chronic illness all ripple through to your periods.

Hormone tests are most useful when timed to the cycle and read in context. The early follicular panel (cycle day 2–4, counting day one as the first day of full bleeding) is the standard baseline and usually includes FSH, LH, oestradiol, prolactin and TSH. Typical early-follicular ranges are FSH 3–10 mIU/L, LH 2–10 mIU/L, oestradiol 20–50 pg/mL, prolactin 5–25 ng/mL and TSH 0.4–4.5 mIU/L, though labs vary slightly.

Reading that panel: high FSH with low oestradiol suggests reduced ovarian reserve or primary ovarian insufficiency; high LH with an LH:FSH ratio above 2:1 suggests PCOS; low FSH and LH point to a hypothalamic or pituitary cause (such as stress- or low-weight-related amenorrhoea); high prolactin suggests High Prolactin in India: Missed Periods and Trouble Conceiving; and an abnormal TSH points to thyroid disease. Each finding directs the next step.

Mid-luteal progesterone (cycle day 21, adjusted for your cycle length) confirms whether you ovulated this cycle — above 5 ng/mL means yes. AMH can be drawn on any cycle day and reflects egg reserve: roughly 1–4 ng/mL is normal in reproductive years, low values suggest reduced reserve, and very high values (above 5–6 ng/mL) often accompany PCOS. AMH costs about ₹800–1,500 at Indian labs — more in AMH and ovarian reserve testing.

Androgen tests (total and free testosterone, DHEAS) are added when PCOS or excess hair growth is suspected; elevated levels confirm the biochemical hyperandrogenism that is one of the Rotterdam criteria. Selectively, doctors may add 17-hydroxyprogesterone or a pituitary MRI. A full hormonal panel at private Indian labs (Dr Lal PathLabs, SRL, Thyrocare, Metropolis) runs about ₹3,000–5,000, often with home sample collection; government labs offer the same tests far cheaper.

Hormonal contraception works by steering the natural cycle: it stops ovulation, thickens cervical mucus, and thins the lining so implantation is unlikely even if an egg were released. Combined oral contraceptive pills contain synthetic oestrogen (usually ethinyl oestradiol) plus a progestin. Steady levels through the active weeks suppress GnRH, LH and FSH, so no follicle matures. The pill-free week produces a withdrawal bleed that looks like a period but isn't one biologically, since no ovulation occurred.

Progestin-only methods (minipills, implants, injections, hormonal IUDs) work mainly through mucus thickening and lining thinning, with variable ovulation suppression. The minipill suppresses ovulation in about half of cycles; the depot injection (DMPA, every three months) suppresses it in nearly all; implants suppress it reliably; and hormonal IUDs act mostly locally on the cervix and lining. For choosing between devices, see copper IUD vs Mirena.

Side effects mirror the hormonal change. Combined methods can cause breakthrough bleeding (mostly in the first 3–6 months), breast tenderness, mood changes, nausea, fluid retention, and rarely blood clots (mainly in smokers, women over 35, or those with clotting risk factors). Progestin-only methods more often cause irregular spotting, acne, mood changes and reduced libido. The right method depends on your age, smoking status, history and goals, and is best chosen with a gynaecologist.

Beyond contraception, these methods regulate cycles in PCOS, reduce heavy bleeding and cramps, treat acne and excess hair, lower endometrial and ovarian cancer risk, and ease PMDD. Fertility returns to baseline after stopping — within 1–3 months for most methods, though DMPA can take 6–12 months. Past use does not cause infertility.

Tracking ovulation helps if you are trying to conceive, using fertility-awareness contraception, or simply want to understand your cycle. Several methods exist, with different accuracy.

Calendar method. Because the luteal phase is fixed at 14 ± 2 days, you can estimate ovulation by subtracting 14 from your average cycle length (day 14 for a 28-day cycle, day 16 for a 30-day cycle). It is a rough guide only and unreliable with irregular cycles.

Basal body temperature (BBT). Progesterone raises your resting temperature by 0.3–0.6°C after ovulation. Measured first thing each morning before getting up (a BBT thermometer costs ₹200–600 at Indian pharmacies), it confirms ovulation only after the fact, so it can't predict the fertile window in advance.

Cervical mucus monitoring. Mucus turns clear, abundant and stretchy (egg-white) just before ovulation, then thick and scant afterwards. With practice this is reasonably reliable — see the cervical mucus method for tracking.

Urine LH kits are the most accurate consumer option, detecting the surge 24–36 hours before ovulation; test daily from about cycle day 10. Smart trackers (Mira, Inito) measure several urine hormones for richer data but cost more (₹6,000–20,000 plus strips). For contraception, fertility-awareness methods have typical-use failure rates of about 12–24% per year — much less reliable than other methods. If you want to use them to avoid pregnancy, learn them properly first via the fertility awareness method guide.

Lifestyle has a real, not minor, effect on cycle hormones — addressing it is genuine treatment for many cycle problems, alongside or before medication. Stress activates cortisol and CRH, which suppress GnRH pulses and can stall ovulation; effects range from mild cycle lengthening to complete loss of periods. Sustained stress management (rest, yoga, therapy, sleep, sharing the load) helps over weeks to months.

Body weight and composition matter because fat tissue makes oestrogen by converting androgens. Very low body fat (often in athletes, dancers or restrictive eating) lowers oestrogen and disrupts cycles, while central obesity raises oestrogen and insulin resistance, feeding into PCOS and irregular cycles. A healthy BMI (about 18.5–24.9) generally supports cycle function; the relationship to PCOS is covered in PCOS and insulin resistance.

Exercise has a U-shaped relationship. Regular moderate activity (about 150 minutes a week, per WHO and ACOG) supports regularity and eases PMS, but excessive exercise with too little fuel (the female athlete triad) disrupts the cycle and weakens bone. The right dose supports health without depleting energy.

Sleep and diet round it out. Aim for 7–9 hours with consistent timing; shift work and poor sleep disrupt cycles. Eat enough (no extreme restriction), with adequate iron and B vitamins — especially important on the vegetarian diets common in India — and limit refined sugar, particularly with PCOS. To align habits with each phase, see cycle syncing your lifestyle.

A few patterns are especially relevant for Indian women. PCOS is common (FOGSI-cited studies estimate roughly 10–20%), along with the insulin resistance and metabolic risk that travel with it. So a cycle-irregularity workup here often includes the full PCOS panel (LH, FSH, oestradiol, testosterone, DHEAS, prolactin, TSH, fasting glucose and insulin, lipids and a pelvic ultrasound), running about ₹3,000–5,000 privately. Start with PCOD vs PCOS explained, then PCOS treatment options.

Thyroid disease is also common and a frequent, fixable cause of irregular cycles; TSH should be checked in any unexplained irregularity. Levothyroxine (Thyronorm, Eltroxin) is inexpensive and usually restores cycles within 1–3 months — see thyroid symptoms in Indian women and thyroid and fertility.

Iron-deficiency anaemia is highly prevalent (NFHS-5 found a large share of reproductive-age women anaemic) and worsens fatigue and heavy bleeding. Ferritin and transferrin saturation, plus iron treatment, belong in routine evaluation — more in iron deficiency in Indian women. Persistently heavy periods deserve their own workup.

Access varies widely. Urban centres have abundant private labs with home collection; tier-3 and rural areas rely more on district hospitals and CHCs, where basic tests are usually available through the public system at low or no cost. Tele-gynaecology (Practo, MFine and similar) offers first consultations around ₹600–1,500. Most relevant medicines — levothyroxine, cabergoline, combined pills, progestins (Primolut N), metformin — are affordable and on the essential-medicines list, but are best taken on a proper prescription rather than bought over the counter.

Cycle variation is normal, but some patterns deserve a gynaecologist's review rather than watchful waiting. Book an appointment if any of the following apply to you.

Seek care promptly if bleeding is so heavy you soak through a pad or tampon every hour for several hours, pass large clots, or feel faint — this can point to anaemia or a treatable cause and is covered in heavy menstrual bleeding.

• ACOG — The Menstrual Cycle and Menstruation
• NICE CKS — Menorrhagia and Amenorrhoea (assessment of menstrual disorders)
• NHS — Periods and the menstrual cycle
• WHO — Physical activity guidelines
• FOGSI — Federation of Obstetric and Gynaecological Societies of India
• ICMR / NFHS-5 — National Family Health Survey (anaemia and women's health data)