How long are eggs viable after ovulation?
Eggs are viable (available to be fertilized by a sperm cell) for about 12-24 hours after ovulation. However, sperm cells are viable in your reproductive tract for up to five days, meaning the fertile window can last six days total. It’s nearly impossible to know you’ve ovulated the moment you do, so it’s important to have regular intercourse in the days leading up to ovulation, not just that day.
During the first half of the menstrual cycle–known as the proliferative, or “follicular” phase–many eggs are developing in follicles in your ovaries, though this does not happen spontaneously. During the beginning of the proliferative phase, your body begins to produce a hormone known as GnRH (gonadotropin-releasing hormone), which signals for FSH (follicle-stimulating hormone) to begin stimulating your follicles to help mature your eggs, and prepare for ovulation.
Follicles produce and release estrogen as they grow, and when it becomes clear which egg is maturing best, the remainder will stop producing estrogen and disintegrate. This sole survivor has now solidified its place as the lone egg available for ovulation. At some point (usually about a day or two before you ovulate), the estrogen released by your dominant follicle reaches a certain threshold, which causes your brain to send instructions to release a new hormone, LH (luteinizing hormone). The surge in LH serves as instructions to your ovary saying, “hey ovary, release that egg!”
About a day or two after you notice the LH surge, your ovary will heed the hormone’s instructions, and release an egg into your fallopian tube, where it has plans to get together with your partner’s sperm cell–this is known as ovulation. At this time, your body will start producing the hormone progesterone, to help thicken your uterine lining and prepare it for pregnancy. If you had intercourse in the five days prior to ovulation, there may be a sperm cell waiting for your egg in the fallopian tube, although intercourse in the 12-24 hours after ovulation can also result in conception.
If your egg successfully meets a sperm and is fertilized within the day or so after ovulation, it will then travel towards your uterus, and implant in the uterine lining, where it will begin producing human chorionic gonadotropin (hCG), the hormone that pregnancy tests search for, and continue the progesterone production. Implantation tends to happen about 7-10 days after fertilization.
If your egg is not fertilized, estrogen and progesterone production will stop, and the thickened uterine lining will begin to disintegrate. When progesterone drops to a certain level, it triggers a menstrual period, and the start of a new cycle.
How do I know if I’ve ovulated?
Some women notice one-sided abdominal cramping or lower backaches when they ovulate, but it’s not always so clear. However, there are certain methods that you can use to determine whether you ovulated, including monitoring your basal body temperature, and using ovulation test strips.
Your basal body temperature (BBT) may vary throughout the menstrual cycle, but it often does so in a consistent way. Women may sometimes notice a slight dip in basal body temperature immediately before ovulation, but there is a quite strong correlation between ovulation and a spike in BBT in the days following ovulation, due to the elevated level of progesterone. Tracking your BBT across multiple cycles can help you figure out how consistent your ovulations are from cycle-to-cycle.
Ovulation tests are another tool you can use to determine if ovulation occurred. Ovulation tests search your urine for the presence of LH, the hormone that spikes in the day or two before ovulation, so ovulation tests can help you identify up to three of your fertile days, as an egg is viable for up to 24 hours after ovulation.
Tracking your basal body temperature and ovulation tests, as well as your symptoms, moods, and cervical fluid are excellent methods of pinpointing your ovulation so that you’re able to have the intercourse needed to conceive while your egg is still viable.
- “Determining Your Fertile Window” American Pregnancy Association. American Pregnancy Association. June 12, 2018. http://americanpregnancy.org/getting-pregnant/fertility-window/