Ovulation, in the simplest terms, is the release of a mature egg from an ovary, which typically occurs 12 to 14 days before the start of the next period. Women who have regular cycles can subtract 14 from period day to get a rough estimate of when ovulation occurs for them. “So, for a woman who has 28- to 30-day cycles, her expected ovulation day would be around cycle day 14 to 16 (give or take a few days); a woman who has a 24-day cycle may be ovulating as early as cycle days 8 to 10, while a woman with a 35-day cycle may be ovulating as late as cycle day 21,” explains Janet Choi, MD, a board-certified reproductive endocrinologist and medical director of CCRM New York. This information is critical for women who are trying to conceive, as the egg is only ripe for fertilization for 12 to 24 hours once it’s released. Watch for these signs that ovulation is imminent.
Even if you’re not trying to conceive, you might notice some effects of your heightened hormones at this time. “Some women experience moodiness, while others experience a greater sense of well-being or an increased libido around ovulation time,” says Dr. Choi. For that you can thank spikes in progesterone and estrogen levels during the week after ovulation.
Ovulation brings other surprising effects: Research from Indiana University’s Kinsey Institute shows that around the time we start ovulating, between day 14 to day 25, we see men’s faces through a different lens. The frontal cortex, which typically manages our self-control, declines a bit, leaving us freer to be attracted to more masculine-looking faces and more likely to engage in risky sexual behavior, the study authors say. Also, as our inhibitions lessen, our memory strengthens. A German study cited in Shape shows that the grey matter in our brain grows, particularly in the hippocampus, leading to improved memory, largely because we’re pumping out high levels of estrogen. Sadly, this window of opportunity—say, to impress friends with our Jeopardy wisdom—closes quickly once we start ovulating and our estrogen and testosterone levels decrease.
That leaves our progesterone levels higher, so we might feel nice and calm—the perfect environment for an egg to take up residence in the uterus. If that happens—hormones surge and a pregnancy likely begins. If it doesn’t happen, progesterone and estrogen levels plummet, leaving us stressed and cranky. Cue the PMS!