In simple high school biology-speak, ovulation is how your body releases an egg to be fertilized by sperm, in order for you to get pregnant. The process is essentially a chain reaction from the release of several hormones. Here's the gist of how it works:
• Each month, your body prepares for the possibility that you may become pregnant by triggering a hormone called follicle-stimulating hormone (FSH).
• FSH causes some of your eggs -- located in individual sacs, called follicles -- within your ovaries to start maturing. These follicles, in turn, produce another hormone, estrogen.
• When enough estrogen has been produced, usually anywhere from 12 to 18 days after your cycle begins (if you count the first day of your last period as day one), this triggers the release of a third hormone called luteinizing hormone (LH).
• LH -- which is what's detected in your urine if you track ovulation with a drugstore predictor kit -- triggers your egg to burst from the most mature follicle and enter the fallopian tube. It'll stay there for up to 24 hours, during which time sperm needs to be present for fertilization to take place.
• Meanwhile, the newly empty follicle -- now called the corpus luteum -- begins to produce yet another hormone, progesterone, which prevents your body from releasing more eggs for the duration of the cycle. If you're not pregnant, the corpus luteum functions for about another 12 to 16 days, after which progesterone levels drop, you get your period, and the cycle begins all over again. If you are pregnant, progesterone levels stay elevated, which is why your period goes MIA when you're expecting. --Deborah Gaines