Ovulation is the release of a mature egg from the ovary. The egg survives for 12–24 hours. Sperm can survive in the reproductive tract for up to 5 days. This means the fertile window extends roughly 5 days before ovulation and 1 day after — 6 days total.
When Does Ovulation Happen?
In a textbook 28-day cycle, ovulation occurs on Day 14. In reality, cycles vary. The key relationship: ovulation typically occurs 14 days before your next period, not 14 days after your last one. If your cycle is 32 days, you likely ovulate around Day 18. If it's 24 days, ovulation is around Day 10.
Signs of Ovulation
- •Cervical mucus changes: Near ovulation, mucus becomes clear, slippery, and stretchy — similar to raw egg whites (called "egg white cervical mucus" or EWCM)
- •Basal body temperature (BBT): Temperature rises by 0.2–0.5°F after ovulation and stays elevated. Track daily to identify the pattern.
- •LH surge: Ovulation predictor kits (OPKs) detect the LH hormone surge that triggers ovulation, typically 12–36 hours before the egg releases
- •Mittelschmerz: Some women feel a one-sided, mild cramp on the side of ovulating ovary
Cycle Tracking Methods Compared
- •Calendar method: Predicts based on historical cycle length. Low accuracy for irregular cycles.
- •BBT charting: Confirms ovulation after the fact. Best combined with another method.
- •OPK tests: Detects LH surge 12–36 hours before ovulation. Most actionable for conception timing.
- •Fertility monitors: Advanced OPKs that track both LH and estrogen for a broader window.
- •Ultrasound monitoring: Most accurate; used in fertility treatments.
For couples trying to conceive, having intercourse every 1–2 days during the fertile window maximizes chances. Daily sex is not more effective than every other day, and abstaining for several days to "save up" can reduce sperm motility in some cases.