This process happens once a month and is regulated by different hormones. Some birth control pills work by changing up those hormones so that you don't ovulate. But for those trying to get pregnant, here are some hormones that you should get to know: follicle stimulating hormone (FSH) and lutenizing hormone (LH). The first hormone, FSH, is in charge of getting the egg nice and ready to be released, just like you may get primped up before a big date. The second hormone, LH, is what signals to the ovary that is is go time, and that the egg should be released.
Why is it important to know this? Because when you are trying to get pregnant it good to monitor your ovulation cycle. There are plenty of over the counter fertility tests ( these do the trick) that test for your LH level to surge and that the egg is about to be released (and that it is a good time to plan a date night). It is also a good idea to have your lady parts doctor test these hormones before you try to get pregnant, since if they are not at the right levels you may have some trouble.
While many have been led to believe that we ovulate smack dab in the middle of our cycle (so around day 15), every body is different and you can ovulate much earlier or much later. Some women get a sharp pain when they ovulate (known as mittleschmerz), or a strong sense of smell, or can just sense it. My mittleschmerz is so strong that it makes me double over in pain. It lasts all of 30 seconds, but man does it hurt! Your cervical mucus (or vaginal discharge), also changes (read all about it here), and is a great indication when your body is ready to get pregnant.
So if you are trying to get pregnant, start to get to know your own ovulation cycle. And don't forget that every body is different, and sometimes, every month is different (this may or may not be how I got pregnant by accident with my second child, but that is a story for another day). Start paying attention to the signals your body gives you to let you know that it is ready for some baby making. And then let the fun begin!