Ovulation typically starts about midway through the menstrual cycle. For an average 28-day cycle, ovulation occurs around day 14, which is roughly 14 days before the next period begins. This timing, however, can vary among women and cycles, with ovulation generally occurring between days 11 and 21 of the cycle. The days leading up to and including ovulation constitute the most fertile phase, and ovulation itself lasts approximately 16 to 32 hours. Ovulation is triggered by a surge in luteinizing hormone (LH) and follicle- stimulating hormone (FSH), causing a mature egg to be released from a follicle in the ovary. The egg then travels through the fallopian tube, where it can be fertilized by sperm within about 12 to 24 hours. If not fertilized, the egg breaks down, and the uterine lining is shed during menstruation. In summary:
- Ovulation starts around the midpoint of the cycle, about 14 days before the next period.
- For a 28-day cycle, this is typically day 14.
- Ovulation lasts 16 to 32 hours.
- The fertile window is generally a few days before ovulation and the day of ovulation itself.
