During ovulation week, your body orchestrates a precise sequence of hormonal shifts, physical changes, and a single decisive moment: the release of an egg from one of your ovaries. This process typically unfolds between days 10 and 16 of your cycle, though the timing varies significantly from person to person. Here’s what’s actually happening inside your body throughout that window.
The Hormonal Buildup Before the Egg Releases
Ovulation doesn’t happen all at once. It’s the result of a hormonal chain reaction that starts days earlier. As a follicle (a small fluid-filled sac containing an immature egg) grows on one of your ovaries, it pumps out rising levels of estrogen. By about day seven of your cycle, estrogen levels have climbed significantly. That rising estrogen sends a signal to your brain to slow down production of FSH, the hormone that originally kicked off follicle growth.
When estrogen reaches a critical threshold, usually around day 13, it triggers a sudden surge of luteinizing hormone (LH). This LH surge is the starting gun for ovulation itself. It launches a cascade of changes inside the follicle that cause the egg to finish maturing and the follicle wall to weaken. Ovulation follows 28 to 36 hours after the LH surge begins, and 8 to 20 hours after LH hits its peak. This is why ovulation predictor kits, which detect LH in your urine, can give you roughly a day’s notice before the egg actually releases.
What Happens When the Egg Releases
The follicle that’s been growing your egg reaches roughly 18 to 28 millimeters in diameter before it ruptures, about the size of a grape. When it breaks open, the egg is expelled along with some fluid and sometimes a small amount of blood. This is the moment of ovulation.
The egg doesn’t just float aimlessly. The ends of your fallopian tubes are lined with finger-like projections called fimbriae that extend over the surface of your ovary and actively catch the egg. Tiny hair-like structures on these projections beat rapidly toward the uterus, sweeping the egg into the fallopian tube. From there, the egg travels slowly down the tube over the next several days.
Once released, the egg survives for less than 24 hours. That’s the entire window in which fertilization can occur. Sperm, by contrast, can survive inside the reproductive tract for up to five days. This mismatch is why the fertile window extends well beyond ovulation day itself.
Your Fertile Window Is Wider Than You Think
The so-called “fertile window” spans roughly six days: the five days before ovulation plus the day of ovulation itself. Because sperm can wait in the fallopian tubes for days, sex that happens several days before the egg releases can still result in pregnancy. But once the egg has been out for about 24 hours without being fertilized, that window closes until the next cycle.
A common misconception is that ovulation always falls on day 14. In reality, ovulation most frequently occurs between days 12 and 16, and almost half of conceptions happen after day 16. If your cycle is shorter or longer than 28 days, your ovulation day shifts accordingly. Relying on a calendar alone isn’t particularly reliable for pinpointing when you ovulate.
Cervical Mucus Changes You Can Track
One of the most noticeable signs of ovulation week is a shift in cervical mucus. Your body produces different types of discharge throughout your cycle, and the pattern follows a predictable progression:
- After your period (days 1 to 4): Dry or sticky, white or light yellow, paste-like texture.
- Days 4 to 6: Slightly damp and sticky, still white.
- Days 7 to 9: Creamy and wet, similar to yogurt in consistency, cloudy in appearance.
- Days 10 to 14: Slippery, stretchy, and clear, resembling raw egg whites. This is peak fertility mucus.
- After ovulation (days 15 to 28): Returns to dry or nearly dry until your period starts.
The egg-white mucus phase typically lasts three to four days. This type of mucus is designed to help sperm travel more easily through the cervix. If you’re tracking your cycle, this is the single most useful physical sign that you’re in your fertile window.
Ovulation Pain and Other Physical Signs
Some people feel ovulation happening. The sensation, sometimes called mittelschmerz (German for “middle pain”), is a cramping or sharp twinge on one side of the lower abdomen. It can last anywhere from a few minutes to a couple of days. The pain likely comes from two sources: the stretching of the ovary’s surface as the follicle grows, and the irritation caused by fluid or blood from the ruptured follicle hitting the abdominal lining.
Not everyone experiences this. Some people feel it every cycle, others only occasionally, and many never notice it at all. When it does occur, it’s typically mild. Severe or persistent pain during this time is worth mentioning to a healthcare provider, as it can sometimes signal other conditions like ovarian cysts or endometriosis.
Other signs that can show up during ovulation week include breast tenderness, mild bloating, a slight increase in sex drive, and heightened senses of smell or taste. These are all driven by the hormonal shifts happening behind the scenes.
The Temperature Shift After Ovulation
Your basal body temperature, your lowest resting temperature taken first thing in the morning, rises slightly after ovulation. The increase is small: less than half a degree Fahrenheit for most people, though it can range from 0.4°F to 1°F. This rise is caused by progesterone, which your body starts producing in larger amounts after the egg is released.
The catch is that this temperature shift only confirms ovulation after it has already happened. It won’t predict it in advance the way cervical mucus or an LH test can. But if you track your temperature over several months, you can start to see your personal pattern and estimate when ovulation is likely to occur in future cycles.
What Happens Right After Ovulation
Once the egg leaves the follicle, the empty sac doesn’t just disappear. It rapidly transforms into a new structure called the corpus luteum, a yellow mass of cells that takes shape where the follicle once was. This structure seals the break in the ovary and begins producing progesterone and estrogen.
Progesterone is the dominant hormone of the second half of your cycle. It thickens the uterine lining, preparing it for a potential embryo. It also raises your body temperature and can cause symptoms like bloating, mood changes, and breast soreness in the days following ovulation. If the egg isn’t fertilized, the corpus luteum breaks down after about 10 to 14 days, progesterone drops, and your period starts. If fertilization does occur, the corpus luteum keeps producing progesterone to support the early pregnancy until the placenta takes over.
This entire sequence, from the hormonal buildup to the egg’s release to the corpus luteum’s formation, repeats each cycle. The process is tightly timed but not rigidly fixed, which is why your cycle length, symptoms, and ovulation day can vary from month to month even when everything is working normally.