Ovulating means your ovary is releasing a mature egg into your fallopian tube, where it can potentially be fertilized by sperm. This happens once per menstrual cycle, typically around 10 to 16 days before your next period starts. The entire event is brief, but it’s the single point in your cycle when pregnancy is possible, and it triggers hormonal shifts that affect how you feel for the rest of the month.
What Happens Inside Your Body
Ovulation is the result of about two weeks of preparation. Starting at the beginning of your cycle, several small fluid-filled sacs called follicles begin growing inside your ovaries. Each follicle contains an immature egg. By around days 10 to 14, one follicle has outgrown the rest and becomes the dominant one, housing a fully mature egg.
At that point, your brain sends a sudden surge of a hormone called luteinizing hormone (LH). This spike is the trigger. It causes the dominant follicle to rupture, releasing the egg from the surface of the ovary. The egg is then swept into the nearest fallopian tube by tiny finger-like projections. From release to the end of its viability, the egg lives for less than 24 hours. The highest chance of fertilization occurs when sperm meet the egg within 4 to 6 hours of its release.
After the egg leaves, the empty follicle transforms into a temporary structure called the corpus luteum. Its primary job is producing progesterone, a hormone that thickens the uterine lining and prepares it to support a pregnancy. If no fertilized egg implants, the corpus luteum breaks down after about two weeks, progesterone drops, and your period begins.
When Ovulation Typically Happens
The textbook answer is day 14 of a 28-day cycle, but that only applies if your cycle is exactly 28 days long. Normal cycles range from 21 to 35 days, and ovulation timing shifts accordingly. A more reliable rule: ovulation tends to occur 10 to 16 days before your next period, not a fixed number of days after the last one. So if your cycle runs 32 days, you’re more likely ovulating around day 16 to 22, not day 14.
This distinction matters because the days before and during ovulation are your fertile window. Sperm can survive inside the reproductive tract for 3 to 5 days, so pregnancy is possible from intercourse that happens several days before ovulation, not just on the day itself. Combined with the egg’s short lifespan of under 24 hours, your total fertile window is roughly six days per cycle: the five days leading up to ovulation plus the day of ovulation.
Physical Signs You May Notice
Your body gives off several signals around ovulation, though not everyone notices them.
The most reliable one is a change in cervical mucus. In the days leading up to ovulation, discharge becomes wetter, clearer, and stretchy, often compared to raw egg whites. This consistency helps sperm travel more easily through the reproductive tract. After ovulation, mucus typically becomes thicker and less noticeable.
Some people experience a distinct pain on one side of the lower abdomen, sometimes called mittelschmerz. It can feel like a dull ache similar to menstrual cramps, or a sharp, sudden twinge. The pain occurs on the side of whichever ovary is releasing the egg that cycle, and it usually lasts anywhere from a few minutes to a few hours, though it can occasionally persist for a day or two. Slight spotting can accompany it.
A subtler sign is a small rise in your resting body temperature. After ovulation, basal body temperature increases by less than half a degree Fahrenheit, sometimes as little as 0.4°F or as much as 1°F. This shift only confirms ovulation after the fact, since the temperature stays elevated until your next period begins.
How to Track Ovulation
If you’re trying to get pregnant or avoid pregnancy, there are a few ways to pinpoint when ovulation is happening.
- Ovulation predictor kits (OPKs) are urine-based tests that detect the LH surge that triggers egg release. They’re widely available at pharmacies. Quality varies, though. Research presented to the Association for Diagnostics & Laboratory Medicine found that of three digital ovulation tests available in the U.S., only one reliably detected ovulation to within one day in about 95% of women tested. The other two were accurate in roughly half of women. Choosing a well-reviewed digital test matters.
- Basal body temperature tracking involves taking your temperature first thing every morning before getting out of bed. You’re looking for a sustained temperature rise over several cycles to identify your pattern. Because the shift happens after ovulation, this method works best for learning your typical timing rather than predicting the exact day in real time.
- Cervical mucus monitoring is free and immediate. Checking for the egg-white consistency each day can help you identify your most fertile days as they’re happening.
Many people combine two or three of these methods for a clearer picture, since each has limitations on its own.
When Ovulation Doesn’t Happen
Not every cycle produces an egg. Occasional missed ovulation is common and not necessarily a sign of a problem. It happens more frequently during certain life stages: the first few years after periods begin, during breastfeeding, and during the transition to menopause.
Chronic lack of ovulation, called anovulation, has a wider range of causes. Polycystic ovary syndrome (PCOS) is one of the most common. It involves elevated levels of androgens that interfere with follicle development. Thyroid disorders, particularly an underactive thyroid, can also disrupt the hormonal chain reaction that leads to egg release.
Lifestyle factors play a significant role too. Very low body weight, often from restrictive eating or intense long-term exercise, can shut down the hormonal signals needed for ovulation. On the other end, obesity can cause the body to produce excess androgens, creating a similar disruption. Chronic high stress affects the same cascade of hormones, specifically the signals from the brain that tell the ovaries to prepare and release an egg. Certain medications, including some psychiatric drugs and anabolic steroids, can also suppress ovulation.
If you’re having irregular periods, cycles shorter than 21 days, cycles longer than 35 days, or no periods at all, those are signs ovulation may not be occurring regularly. The pattern of your period is one of the most accessible indicators of whether your body is ovulating each month.