A: Pregnancy occurs after ovulation, when the egg is released into the body and then fertilized by sperm. What a lot of people don’t realize, though, is that once you’ve ovulated, you have just about a 12 hour period of time to conceive.
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That’s because the lifespan of an egg, once it has ovulated, is only about 24 hours — which means that if that egg is not fertilized within the first 12 hours after ovulation, conception is likely not going to happen.
Because of this small post-ovulation window, it’s important to have sex in advance of ovulation, if you can. Sperm can survive inside your cervix for about 72 hours, so having intercourse in the three day-span before you ovulate will give you higher chances of getting pregnant. That way, by the time the egg is released, there’s already sperm inside the cervical reservoirs waiting to fertilize it.
One of the most surefire ways to know when you’re going to ovulate is to use over-the-counter ovulation strips, which help you identify when you’re about to ovulate — and thus, when you should be having sex in order to maximize the likelihood of conception.
—Reproductive endocrinologist and infertility specialist Laura Detti, MD