The Ovulatory Phase: Your Fertile Window Explained
Ovulation is the release of a mature egg from the ovary, usually about 12 to 16 days before your next period starts. It's triggered by a sharp spike in luteinizing hormone (the "LH surge"), which follows estrogen reaching its peak. The egg survives for only 12 to 24 hours, but because sperm can live up to 5 days, the fertile window (the days when sex can lead to pregnancy) spans roughly the 5 days before ovulation through the day of ovulation itself.
Hormones through the cycle
Estrogen: Peaks just before ovulation, then falls sharply.
Progesterone: Still low, about to start rising.
LH: Surges sharply. This spike is what triggers the egg's release.
FSH: A smaller rise accompanies the LH surge.
A simplified illustration of estrogen, progesterone, LH and FSH across a typical 28-day cycle. Individual levels and timing vary, and this is not a lab measurement.
As the dominant follicle matures, its estrogen output peaks. That peak, sustained for about a day, triggers the brain's pituitary gland to release a large surge of luteinizing hormone (LH). This is what most ovulation tests actually detect.
Roughly 24 to 36 hours after the LH surge begins, the mature follicle ruptures and releases its egg. The egg can only be fertilized for 12 to 24 hours, which is why the days before ovulation, when sperm are already waiting, matter more than the day itself.
Some people notice a one-sided lower abdominal twinge around ovulation (sometimes called mittelschmerz), a change in cervical mucus to a clearer, stretchier texture, or a temporary rise in energy and libido. Not everyone notices any of these signs, and their absence does not mean ovulation is not happening.
Cycle syncing: nutrition & movement
| Focus | Nutrition | Movement |
|---|---|---|
| Around peak estrogen | Fiber-rich vegetables and flaxseed. | Energy is often at its highest, a common time for higher-intensity training or activities that need focus and coordination. |
| Anti-inflammatory support | Fatty fish, olive oil, and colorful vegetables. | Group classes or social workouts can suit the sociability many people report around ovulation. |
| Hydration | Extra water and electrolytes if training intensity increases. | Keep listening to your body. Mid-cycle pain (mittelschmerz) is common and usually mild, but sharp or severe pain is worth checking with a doctor. |
These are general, low-risk wellness suggestions, not medical treatment. Evidence for timing diet and exercise to cycle phase ("cycle syncing") is still limited.
Find your own dates
Enter your usual cycle to see roughly which days fall into each phase for you.
Your estimated phase dates this cycle
Menstrual Phase
1–5
Follicular Phase
6–11
Ovulatory Phase
12–15
Luteal Phase
16–28
Track your fertile window privately
Bloom Private's PhaseCalculator engine reads the dates you log and works out which phase you're in, entirely on your iPhone. No accounts, no servers, and nothing to sell: your cycle data stays on your iPhone unless you choose to export it or turn on Apple Health.
Frequently asked questions
Signs can include a one-sided pelvic twinge, clear stretchy cervical mucus, or a small rise in basal body temperature after ovulation. Ovulation predictor kits detect the LH surge and are the most direct at-home method.
About 6 days: the 5 days before ovulation, plus the day of ovulation itself, because sperm can survive up to 5 days while the egg survives only 12 to 24 hours.
No, day 14 only applies to a 28-day cycle where ovulation happens 14 days before the next period. Shorter or longer cycles shift ovulation earlier or later; Bloom Private estimates it from your own cycle length.
Explore the other phases
Sources
This page is for general education, not medical advice, and Bloom Private is not a contraceptive method. Talk to a healthcare professional about your own cycle and symptoms.