The menstrual cycle has four distinct stages: menstruation, the follicular phase, ovulation, and the luteal phase. A typical cycle lasts 21 to 34 days in adults, counted from the first day of one period to the first day of the next. Each stage is driven by shifting hormone levels that prepare the body for a possible pregnancy, then reset when pregnancy doesn’t occur.
Menstruation (Days 1 to 7)
Menstruation is the stage most people think of as “the period.” It starts when hormone levels drop at the end of the previous cycle, signaling the uterus to shed its lining. That lining exits the body as menstrual blood. Bleeding typically lasts 3 to 7 days, and most periods involve less than 45 mL of actual blood loss, roughly 2 to 3 tablespoons.
Cramping, fatigue, and bloating are common during this phase because the uterus contracts to help shed its lining. Some people also experience headaches, lower back pain, or mood changes as hormone levels bottom out. Cervical fluid is minimal right after bleeding stops and tends to be dry or slightly tacky.
If you’re soaking through a pad or tampon every hour for more than two hours in a row, passing clots larger than a quarter, or bleeding for longer than seven days, that crosses the threshold for heavy menstrual bleeding and is worth bringing up with a healthcare provider.
The Follicular Phase (Days 1 to 14)
The follicular phase actually overlaps with menstruation because it begins on day one of your period. It lasts about 13 to 14 days, though this is the most variable part of the cycle. If your cycles tend to run longer or shorter than average, the follicular phase is usually the reason.
Here’s what’s happening inside: a signal from the brain’s pituitary gland triggers the ovaries to start developing small fluid-filled sacs called follicles. Each follicle contains an immature egg. Several follicles begin growing at once, but eventually one becomes dominant, outpacing the others. That dominant follicle pumps out rising levels of estrogen, which does two things. First, it thickens the uterine lining to prepare for a potential pregnancy. Second, it signals the brain to dial back the hormone that started follicle growth in the first place, causing the remaining follicles to wither away.
As estrogen rises through this phase, many people notice improved energy, clearer skin, and a more stable mood compared to the days of menstruation. Cervical fluid gradually shifts from sticky and white to creamy and wet, reflecting the body’s preparation for ovulation.
Ovulation (Around Day 14)
Ovulation is the shortest stage, lasting only about 24 hours. It’s triggered by a sharp spike in luteinizing hormone (LH) from the pituitary gland. That LH surge begins roughly 36 hours before the egg is released and lasts about 24 hours. This is what at-home ovulation test strips detect.
When the surge peaks, the dominant follicle ruptures and releases a mature egg into the fallopian tube. The egg survives for only 12 to 24 hours after release. Sperm, however, can live inside the reproductive tract for up to five days. That means the fertile window stretches from about five days before ovulation through the day of ovulation itself, a span of roughly six days. The highest chance of conception occurs when sperm and egg meet within four to six hours of the egg’s release.
Cervical fluid becomes its most distinctive during this window: stretchy, slippery, and clear, often compared to raw egg whites. Some people feel a mild twinge or one-sided pelvic ache when the egg is released, sometimes called mittelschmerz. Libido, energy, and confidence often peak around ovulation as estrogen reaches its highest point in the cycle.
The Luteal Phase (Days 15 to 28)
Once the egg leaves the follicle, the empty sac doesn’t just disappear. It transforms into a temporary structure called the corpus luteum, a small yellowish mass of cells on the surface of the ovary. The corpus luteum’s primary job is producing progesterone, the hormone that maintains and enriches the uterine lining so a fertilized egg could implant and grow.
The luteal phase lasts about 14 days and is remarkably consistent from cycle to cycle, even in people whose overall cycle length varies. Progesterone dominates this phase, and it brings a noticeably different set of physical sensations. Cervical fluid dries up quickly after ovulation. Body temperature rises slightly. Breast tenderness, bloating, food cravings, and mood shifts are all common, especially in the final week. These are the classic premenstrual symptoms, driven by the rise and then sharp fall of progesterone.
If the egg is fertilized and implants, the body produces a pregnancy hormone (hCG) that keeps the corpus luteum alive and producing progesterone. If pregnancy doesn’t occur, the corpus luteum breaks down, progesterone and estrogen plummet, and the uterine lining begins to shed. That brings you back to day one: menstruation.
How to Track Your Own Cycle
Knowing where you are in your cycle can help you anticipate symptoms, plan around your energy levels, or identify fertility windows. The simplest approach is tracking the first day of each period on a calendar or app for a few months to learn your personal cycle length. Adults typically fall in the 21 to 34 day range.
Cervical fluid offers a practical, real-time signal of your current phase:
- Dry or tacky: early follicular phase, just after your period
- Creamy and white: mid-follicular phase, approaching ovulation
- Stretchy and clear: ovulation window, peak fertility
- Dry again: luteal phase, after ovulation
Cycles in the first few years after a person’s first period can be longer and less predictable, with a normal range stretching from 21 to 45 days. By the third year, 60 to 80 percent of cycles settle into the adult pattern. Consistently irregular cycles, extremely painful periods, or cycles that suddenly change after being stable are all signals worth paying attention to.