Menstrual Cycle Phases, Day by Day: Hormones, Body Signs and What is Normal

There are four menstrual cycle phases: menstrual, follicular, ovulation and luteal. In a 28-day example, bleeding runs from day 1 to about day 5, ovulation falls around day 14, and the luteal phase fills the last two weeks. Day 14 is only an average; the follicular phase changes length, while the luteal phase stays steadier.

Menstrual cycle phases diagram: the menstrual, follicular, ovulation, and luteal phases across a 28-day cycle.

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Your cycle is counted from the first day of real bleeding

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What are the four menstrual cycle phases?

Your cycle is counted from the first day of real bleeding to the day before your next period starts. The average cycle is 28 days, and anything from 21 to 35 days is normal (NHS). FIGO, the international gynaecology body, uses a slightly wider adult range of 24 to 38 days (FIGO 2018, summarised in the MSD Manual).

The phases overlap more than most diagrams suggest: the follicular phase begins on day 1, because the ovary starts preparing a new egg while the old lining is still shedding. For the bigger picture on cycle length and what counts as regular, see our guide to the menstrual cycle.

The four phases at a glance

This table sets out the 4 phases of the menstrual cycle in a 28-day example, with the main event and the hormone that leads it. Your own day numbers may be earlier or later.

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Phase	Typical days (28-day cycle)	What happens	Lead hormone
Menstrual	Days 1 to 5	Uterine lining sheds as the period	Estrogen and progesterone at their lowest
Follicular	Day 1 to ovulation (about day 13)	Follicles grow, one leads, lining rebuilds	FSH, then rising estrogen
Ovulation	Around day 14	Mature egg is released	LH surge
Luteal	Ovulation to next period (days 15 to 28)	Corpus luteum supports the lining	Progesterone

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Why doesn't ovulation always happen on day 14?

Ovulation shifts because the follicular phase varies in length from cycle to cycle. In a study of 612,613 cycles, the average was 16.9 days, compared with 12.4 days for the luteal phase, and only 13% of cycles were exactly 28 days long (Bull et al., npj Digital Medicine 2019). The day 14 rule comes from the textbook model, not from real cycles.

Most of us learned the menstrual cycle from the NCERT Class 12 biology model: menstrual days 1 to 5, follicular days 6 to 13, ovulation on day 14, and luteal days 15 to 28 (NCERT chapter on SATHEE, IIT Kanpur). It is a useful teaching model, but real cycles rarely follow it.

The authors of that study, the largest real-world cycle study, stated plainly that the belief that ovulation happens on day 14 is incorrect (Bull et al., npj Digital Medicine 2019).

The follicular phase shows the most variation (about 10 to 30 days in that study), while the luteal phase stays within about 7 to 17 days. So a long cycle usually means late ovulation. One caveat: the data came from fertility app users, not an Indian sample.

What happens in each phase of the menstrual cycle, day by day?

In a 28-day cycle, days 1 to 5 are the period, days 6 to 13 are the late follicular phase as a follicle matures, ovulation falls around day 14, and days 15 to 28 are the luteal phase, when progesterone prepares the lining for a possible pregnancy. The NHS places ovulation 10 to 16 days before the next period.

Menstrual phase (days 1 to 5)

With estrogen and progesterone low, the lining breaks down and leaves the body. A typical period lasts 2 to 7 days and loses about 20 to 90 mL of blood, roughly 1 to 5 tablespoons (NHS). If you want a fuller picture of flow, colour and duration, read what counts as a normal period.

Follicular phase (day 1 to ovulation)

The pituitary gland releases FSH (follicle-stimulating hormone), which wakes up a group of follicles in the ovary. By the second week, one follicle usually takes the lead and pours out estrogen. That estrogen rebuilds the lining and makes cervical mucus wetter and clearer. On a follicular monitoring scan, the doctor measures the lead follicle every two or three days.

Ovulation phase (around day 14 in a 28-day cycle)

High estrogen triggers a sharp surge of LH (luteinising hormone), and the follicle releases its egg. After a positive urine LH test, ovulation usually follows within about 36 hours, and the egg survives only 12 to 24 hours (Cleveland Clinic). Some women feel a brief one-sided ache. Mucus is often clear and stretchy, like raw egg white. Our guide on how to track ovulation naturally covers these signs in detail.

Luteal phase (ovulation to the next period)

After ovulation, the follicle that released the egg turns into a small gland, the corpus luteum, which makes progesterone to soften the lining for implantation. Most luteal phases last 12 to 14 days; anything from 10 to 17 days is normal, and under 10 days counts as short (Cleveland Clinic). If no embryo implants, progesterone falls and the next period begins.

An embryo that does form implants about 6 to 7 days after fertilisation (NCERT, SATHEE).

Day-by-day menstrual cycle chart for a 28-day cycle

This chart walks through the menstrual cycle phases day by day in a textbook 28-day cycle, in short blocks of days, with hormones, the lining as it looks on ultrasound, body signs, and fertility. Lining ranges are approximate (Radiopaedia).

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Days	Phase	Hormones	Lining (approx.)	What you may notice	Chance of pregnancy
1 to 2	Menstrual, early follicular	Estrogen and progesterone low; FSH starts rising	Shedding	Heaviest flow, cramps, tiredness	Very low
3 to 5	Menstrual, early follicular	FSH rising	2 to 4 mm as bleeding ends	Flow lightens	Low
6 to 9	Follicular	Estrogen climbing	5 to 7 mm	Dry or sticky mucus, energy often returning	Low but rising
10 to 13	Late follicular, fertile window opens	Estrogen near its peak	Up to about 11 mm	Creamy, then clear slippery mucus	High
14	Ovulation (average)	LH surge	About 11 mm	Egg white mucus, possible one sided ache	Highest
15 to 16	Early luteal	Progesterone rising	7 to 16 mm	Temperature rises and stays up, mucus thickens	Falling fast
17 to 23	Mid luteal	Progesterone at its peak, around day 21	7 to 16 mm	Few signs; implantation window if conception happened	Very low
24 to 28	Late luteal	Progesterone and oestrogen fall if not pregnant	Prepares to shed	Bloating, breast tenderness, mood changes for some	Very low

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How the phases shift in 24, 32 and 35 day cycles

A rough rule is that ovulation happens about 14 days before the next period, so you subtract 14 from your usual cycle length. The table applies that rule; the real gap is anywhere from 10 to 16 days (NHS), so treat these as estimates.

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Usual cycle length	Estimated ovulation day	Likely fertile days	Follicular phase	Luteal phase
24 days	Day 10	Days 5 to 10	About 10 days	About 14 days
28 days	Day 14	Days 9 to 14	About 14 days	About 14 days
32 days	Day 18	Days 13 to 18	About 18 days	About 14 days
35 days	Day 21	Days 16 to 21	About 21 days	About 14 days

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Cycles longer than 35 days, or ones that jump around, often mean ovulation is late or missing in some months. This is common with PCOS, which an ICMR-funded national study found in 7.2% to 19.6% of Indian women aged 18 to 40, depending on the diagnostic criteria used (JAMA Network Open 2024). Our PCOS and fertility guide explains what that means for conceiving.

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How do hormones change in each phase of the menstrual cycle?

Four hormones run the cycle. FSH rises first and grows follicles, estrogen climbs as the lead follicle matures, a sudden LH surge releases the egg, and progesterone from the corpus luteum dominates the second half. If pregnancy does not happen, estrogen and progesterone both fall, and that drop starts the next period.

FSH: rises slightly in the last days of one cycle and the first days of the next, then eases off once one follicle takes over.

LH: stays low for most of the cycle, then surges sharply just before ovulation. This surge is what urine ovulation kits detect, and ovulation usually follows within about 36 hours (Cleveland Clinic).

Estrogen: builds through the follicular phase, peaks just before the LH surge, dips, then has a smaller second rise in the luteal phase.

Progesterone: stays low until ovulation, then rises and peaks about a week later. A blood test timed to that peak tells your doctor whether you ovulated.

hCG: appears only if an embryo implants, and keeps progesterone high so the period does not come.

Hormone levels by phase

This table links menstrual cycle phases and hormones, giving the direction of each hormone in each phase. These are relative levels, not lab values; the normal blood ranges depend on the laboratory and the cycle day.

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Phase	FSH	LH	Estrogen	Progesterone
Menstrual	Rising slightly	Low	Low	Low
Follicular	Moderate, then easing	Low	Rising steadily to a peak	Low
Ovulation	Small surge	Sharp surge	Peaks, then dips	Starts to rise
Luteal	Low	Low	Second, smaller rise, then falls	High, peaks mid-phase, falls if not pregnant

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Endometrial thickness by phase

The lining of the uterus (endometrium) changes thickness through the cycle, and a transvaginal scan can measure it. These approximate ranges are what doctors see on ultrasound (Radiopaedia).

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Phase	Approximate thickness on ultrasound
During the period	2 to 4 mm
Early follicular (days 6 to 14)	5 to 7 mm
Late follicular, just before ovulation	Up to 11 mm
Luteal (secretory)	7 to 16 mm

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Body signs you can track by phase

Two home signs show where you are in your cycle. Cervical mucus turns wetter, clearer, and stretchier as ovulation approaches. Basal body temperature, taken on waking, rises slightly after ovulation, usually by about 0.2 to 0.3 C, and stays up until your period (Mayo Clinic; Cleveland Clinic). That rise confirms ovulation afterwards; it cannot predict it.

For ways to improve mucus quality, see how to increase fertile cervical mucus.

How do mood and energy change in each phase of the menstrual cycle?

Many women feel lower energy during the period, a gradual lift through the follicular phase, and more irritability, bloating, or low mood in the last week before bleeding. Hormone shifts can affect mood and energy, and can worsen conditions such as depression, migraine and IBS at certain points in the cycle (Office on Women's Health).

Mood and energy by phase

The table below links menstrual cycle phases and moods, describing what women commonly report in each phase, with an honest note on how strong the evidence is. Use it as a guide to notice your own pattern, not as a rulebook.

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Phase	Mood	Energy	Evidence note
Menstrual	Relief for some, low or tearful for others	Often lower, especially with heavy flow	Heavy periods are the most common cause of iron deficiency anaemia in women of reproductive age (OWH)
Follicular	Often steadier, more positive	Usually improving	Commonly reported; individual studies vary
Ovulation	Some feel more sociable or notice higher libido	Often good	Small effects; many women notice nothing
Late luteal	Irritability, anxiety, low mood possible	Tiredness, poor sleep, cravings	Over 90% of women report some premenstrual symptoms (OWH)

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There is little evidence that rigid "cycle syncing" diets or workouts help. Daily movement, good sleep, and enough iron from dal, rajma, chana, and leafy greens are a better base. If every period leaves you exhausted, ask for an iron check rather than blaming hormones.

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PMS or PMDD: how to tell the difference

PMS (premenstrual syndrome) is common and usually manageable. Doctors usually suspect PMS when the same symptoms show up in the 5 days before bleeding, ease within 4 days of the period starting, and repeat for at least 3 cycles running (OWH). PMDD (premenstrual dysphoric disorder) sits at the severe end: under 5% of women of childbearing age have it, and the depression, anxiety or anger is strong enough to disrupt work and relationships. About half of women seeking PMS relief also have another condition, such as depression or anxiety (OWH), so track symptoms against cycle days for two or three months before your visit.

How much do menstrual cycle tests cost at Cloudnine Fertility?

For irregular or painful cycles, or when trying to conceive, a Cloudnine Fertility specialist may suggest phase-timed tests. Indicative costs are ₹ 800 to ₹ 1,500 for a consultation and ₹ 3,500 to ₹ 7,000 for a follicular monitoring series. Progesterone is checked about 7 days after ovulation, which is day 21 only in a 28-day cycle.

Indicative cost of cycle phase tests at Cloudnine Fertility

This table lists every test mentioned in this article, when in the cycle it is usually done, and the indicative cost range across Cloudnine Fertility centres. Indicative ranges at Cloudnine Fertility; final cost confirmed at consultation.

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Test	What it checks	When in the cycle	Indicative cost (INR)
Specialist consultation	History, cycle pattern, which tests you need	Any day	Rs 800 to ₹ 1,500
Follicular monitoring series (serial transvaginal scans)	Follicle growth, ovulation day, lining thickness	From about day 8 or 9 until ovulation	Rs 3,500 to ₹ 7,000
Serum progesterone	Whether ovulation happened	About 7 days after ovulation	Rs 800 to ₹ 1,500
Serum oestradiol	Follicle activity and oestrogen level	Early follicular or during monitoring	Rs.5,000 to Rs.9,500
Ovarian reserve panel incl LH (with FSH and AMH)	Ovarian reserve and hormone balance	Days 2 to 5	₹ 5,000 to ₹ 6,500
TSH and prolactin	Thyroid and prolactin, both of which can shift ovulation	Any day	₹ 400 to ₹ 1,200
CBC / ferritin	Anaemia and iron stores with heavy periods	Any day	₹ 1,000 to ₹ 2,500

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The total depends on how many scans you need before ovulation. If ovulation is supported with medicines, ovulation induction and cycle monitoring is planned as a package after the first consultation.

When should you see a gynaecologist about your cycle?

See a gynaecologist if your cycles are regularly shorter than 21 days or longer than 35 days, if bleeding lasts more than 7 days, or if the gap between your shortest and longest cycle is more than 7 to 9 days. Go sooner for very heavy bleeding, bleeding after sex or between periods, or mood changes that disrupt daily life.

Signs your cycle needs a check

This table lists specific warning signs and why each one matters. One unusual month is rarely a concern; a pattern over three months is worth a visit.

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Sign	Why it matters
Cycles under 21 or over 35 days (NHS)	May mean ovulation is irregular or absent
Cycle length varies by more than 7 to 9 days (FIGO 2018)	Outside normal regularity limits
Bleeding for more than 7 days (NHS)	Can point to fibroids, polyps or hormone imbalance
Soaking a pad every 1 to 2 hours, or clots bigger than about 2.4 cm (OWH)	Heavy bleeding that can cause anaemia
Bleeding between periods or after sex (NHS)	Needs examination to rule out cervical or uterine causes
No period for 3 months and not pregnant (OWH)	Ovulation has likely stopped; causes include PCOS and thyroid problems
Not pregnant after 12 months of trying, or 6 months if over 35 (OWH)	Time for a fertility assessment
Premenstrual low mood that disrupts work or relationships	Possible PMDD; thoughts of self-harm need urgent help the same day

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If any of these sound familiar, you can book an appointment with a fertility specialist at Cloudnine Fertility.

Which phase of the menstrual cycle is the most fertile?

The late follicular phase and ovulation day are the most fertile part of the cycle. In a landmark study of 221 women, pregnancy came only from sex during a six-day window ending on ovulation day, with the chance rising from about 10% five days before ovulation to about 33% on the day itself (Wilcox et al., NEJM 1995).

Chance of pregnancy by day around ovulation

This table summarises the Wilcox findings. Sperm can survive 3 to 5 days, while the egg lasts only 12 to 24 hours (Cleveland Clinic), which is why the window sits mostly before ovulation.

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Timing of sex	Chance of conception from that day
6 or more days before ovulation	No pregnancies observed in the study
5 days before ovulation	About 10%
4 to 1 days before ovulation	Rising each day
Ovulation day	About 33%
The day after ovulation onward	No pregnancies observed in the study

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Counting backwards is unreliable in an irregular cycle. Our article on when you are most fertile compares the methods, from mucus checks to scans.

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