The 4 phases of the menstrual cycle

Menstrual cycle phases come in four stages: menstrual, follicular, ovulation and luteal. They repeat every cycle, though the exact length varies from woman to woman, and even cycle to cycle for the same woman.

In a cycle that averages 28 days, here's roughly how they line up:

• Menstrual phase (about days 1 to 5): your period, when the uterine lining sheds and hormones are at their lowest.
• Follicular phase (about days 1 to 13): overlaps with your period at the start. Follicles in your ovaries mature and estrogen climbs.
• Ovulation (around day 14): a mature egg is released, triggered by a surge in luteinizing hormone (LH).
• Luteal phase (about days 15 to 28): progesterone rises to prepare the uterine lining, then both progesterone and estrogen drop sharply if you don't get pregnant, which brings on your next period.

The follicular and luteal phases aren't the same length for everyone. Follicular phase length is the main reason total cycle length varies between women, while the luteal phase tends to stay closer to the same number of days each cycle.

During the menstrual phase, the top layer of your uterine lining, built up the cycle before, leaves your body as your period. Cramps come from the uterus contracting to push this lining out. Energy is often lower here, especially on the first day or two.

In the follicular phase, your ovaries grow a batch of follicles, one of which will mature into the egg you ovulate. Rising estrogen thickens the uterine lining again and tends to lift energy and mood as the phase goes on.

Ovulation is brief, usually a single day, though you're fertile for a few days around it because sperm can survive while they wait. Estrogen peaks just before the egg releases, then drops fast.

The luteal phase starts once the egg is released. The empty follicle, now called the corpus luteum, produces progesterone to keep the uterine lining ready for a possible pregnancy. If no pregnancy happens, the corpus luteum breaks down around day 22 to 24, and progesterone and estrogen both fall, which triggers your next period and often the physical and mood symptoms of PMS. Symptoms in each phase of your cycle breaks these down in more detail.

Four hormones drive the whole cycle: follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen and progesterone.

FSH rises first, telling your ovaries to start growing follicles. As those follicles grow, they release estrogen, which climbs steadily through the follicular phase and peaks just before ovulation. That estrogen peak triggers a surge in LH, which is what actually causes the egg to release.

After ovulation, the ruptured follicle turns into the corpus luteum and starts producing progesterone, which rises through the first half of the luteal phase. Estrogen rises again too, more modestly. If the egg isn't fertilized, the corpus luteum stops working, and both progesterone and estrogen fall sharply in the last few days before your period. That drop is the direct trigger for PMS and PMDD symptoms, not low hormones in general.

Your body's calming response follows the same pattern. A 2019 meta-analysis of 1,004 women across 37 studies found that heart rate variability, a marker of how readily your body can shift into a calm, parasympathetic state, measurably decreases from the follicular phase into the luteal phase. A smaller set of studies within that same review found the steepest drop was from the mid-to-late follicular phase to the premenstrual days, with a similarly large drop from menstruation to the premenstrual days. For a visual walkthrough, see menstrual cycle hormones, phase by phase or the menstrual cycle hormone chart.

Mood and energy don't move in a straight line through the cycle, but a few patterns hold up.

The late follicular phase and ovulation tend to be the high point. Estrogen peaks here, and a 2026 systematic review of eumenorrheic athletes linked this window to better neuromuscular coordination and lower injury risk than the menstrual and premenstrual phases. Many women also feel sharper and more sociable around ovulation.

The luteal phase is more mixed. A 2025 systematic review of 152 athletes found enhanced aerobic and anaerobic capacity during parts of the luteal phase, while the same review found the premenstrual days clearly affected symptom reporting and performance perception. In practice, that often means steady energy early in the luteal phase and a drop in the final days as progesterone and estrogen fall together.

A small randomized trial assigned 50 young women to three menstrual cycles of daily yoga or no intervention and tracked anger, anxiety, mood and autonomic markers across their cycles, testing whether yoga eases premenstrual symptoms. Research into whether structured practices like this ease premenstrual symptoms is still limited, but the luteal days are where most women notice they need it.

If a luteal-phase fight with your partner keeps replaying in your head, Niyora is a PMS and PMDD support app. Its Moon tool lets you write down what happened, see it from another angle, and draft a reply you can sit on for 20 minutes. See how your menstrual cycle affects your mood for more.

Cycle length varies. ACOG Clinical Practice Guideline No. 7 (2023) puts a normal cycle anywhere from 21 to 35 days, with 28 as the average most charts use.

Rough lengths, in a 28-day cycle:

• Menstrual phase: 3 to 7 days of bleeding.
• Follicular phase: about 13 to 14 days, though this is the phase that varies most between women and even between your own cycles.
• Ovulation: the egg survives roughly 12 to 24 hours, though you're fertile for a few days around it.
• Luteal phase: about 11 to 17 days, averaging 14, and far steadier in length than the follicular phase.

For more on what's happening in your lower-hormone week, see the luteal phase: what's happening in your body and mood.

The simplest method: call day 1 the first day of full-flow bleeding, and count forward. Day 14 or so, in an average cycle, is roughly ovulation, and everything after that until your next period is the luteal phase.

A few ways to get more precise:

• Basal body temperature: a small rise after ovulation, sustained through the luteal phase, confirms it happened.
• Cervical mucus: it turns clear and stretchy near ovulation, then dries up in the luteal phase.
• Ovulation predictor kits: detect the LH surge a day or two before the egg releases.
• A cycle or symptom app: logs dates and symptoms so you can see your own pattern over a few months, which matters more than any single cycle.

If you just want a quick answer right now, the cycle phase calculator estimates where you are from your last period's start date.

Niyora also gives you an estimated PMS window based on your dates, so you can see the luteal dip coming instead of being surprised by it, without needing an account.