A woman’s monthly cycle is measured from the first day of her menstrual period until the first day of her next period. On average, a woman’s cycle normally is between 28-32 days, but some women may have much shorter or much longer cycles. Ovulation can be calculated by starting with the first day of the last menstrual period (LMP) or by calculating 12-16 days from the next expected period. Most women ovulate anywhere between Day 11 – Day 21 of their cycle, counting from the first day of the LMP. This is what many refer to as the “fertile time” of a woman’s cycle because sexual intercourse during this time increases the chance of pregnancy. Ovulation can occur at various times during a cycle and may occur on a different day each month. It is important to track your cycle and fortunately, there are a number of free fertility charting tools available to help women identify their peak fertile days.
What's Ovulation?
Ovulation is when a mature egg is released from the ovary, pushed down the fallopian tube, and is made available to be fertilized. Approximately every month an egg will mature within one of your ovaries. As it reaches maturity, the egg is released by the ovary where it enters the fallopian tube to make its way towards waiting for sperm and the uterus. The lining of the uterus has thickened to prepare for the fertilized egg. If no conception occurs, the uterine lining, as well as blood, will be shed. The shedding of an unfertilized egg and the uterine wall is the time of menstruation.
Key Facts:
- An egg lives 12-24 hours after leaving the ovary
- Normally only one egg is released each time of ovulation
- Ovulation can be affected by stress, illness or disruption of normal
- Some women may experience some light blood or spotting during ovulation
- Implantation of a fertilized egg normally takes place 6-12 days after ovulation
- Each woman is born with millions of immature eggs that are awaiting ovulation to begin
- A menstrual period can occur even if ovulation has not occurred
- Ovulation can occur even if a menstrual period has not occurred
- Some women experience pain/aching near ovaries during ovulation called ‘middle pain’
- If an egg is not fertilized, it disintegrates and is absorbed into the uterine lining
How to Track Your Ovulation Cycle:
The Ovulation Cycle Divided into Two Parts:
- The first part of the cycle is called the follicular phase. This phase starts the first day of the last menstrual period (LMP) and continues until ovulation.
This first half of the cycle can differ greatly for each woman lasting anywhere from 7 days to 40 days.
- The second half of the cycle is called the luteal phaseand is from the day of ovulation until the next period begins. The luteal phase has a more precise timeline and usually is only 12-16 days from the day of ovulation.
This ultimately means that the day of ovulation will determine how long your cycle is. This also means that outside factors like stress, illness, and disruption of normal routine can throw off your cycle which then results in changing the time your period will come. So the old thought that stress can affect your period is only partly true. Stress can affect your ovulation which ultimately determines when your period will come, but stress around the time of an expected period will not make it late—it was already determined when it would come 12-16 days earlier!
Fertility Awareness is one way to track when ovulation occurs, and it includes noticing the changes in cervical mucus and using a basal thermometer. Cervical fluid will change to a wet, slippery substance that resembles “egg whites” just before ovulation occurs and until it is over. A basal thermometer helps track a body temperature rise, which signals that ovulation has just occurred.
Another way to track your cycle is through ovulation kits and fertility monitors. Tracking can help a woman get a better idea of when pregnancy can and cannot occur during her monthly cycle. Once ovulation has occurred, there is nothing you can do to increase your chances of pregnancy. Your next step is to begin watching for early pregnancy symptoms. View and print an Ovulation Calendar to better understand your cycle.
From the Menstrual Period to Ovulation (the details you may not know!)
When your menstrual cycle begins, your estrogen levels are low. Your hypothalamus (which is in charge of maintaining your hormone levels) sends out a message to your pituitary gland which then sends out the follicle stimulating hormone (FSH). This FSH triggers a few of your follicles to develop into mature eggs. One of these will develop into the dominant follicle, which will release a mature egg and the others will disintegrate.
As the follicles mature, they send out another hormone, estrogen. The high levels of estrogen will tell the hypothalamus and pituitary gland that there is a mature egg. A luteinizing hormone (LH) is then released, referred to as your LH surge. The LH surge causes the egg to burst through the ovary wall within 24-36 hours and begin its journey down the fallopian tube for fertilization. Ovulation Predictor Kits (OPKs) work by detecting this LH surge. The follicle from which the egg was released is called the corpus luteum, and it will release progesterone that helps thicken and prepare the uterine lining for implantation. The corpus luteum will produce progesterone for about 12-16 days (the luteal phase of your cycle.)
If an egg is fertilized, the corpus luteum will continue to produce progesterone for a developing pregnancy until the placenta takes over. You can begin looking for pregnancy symptoms as early as a week after fertilization. You can also begin testing for pregnancy as early as 7-10 days past your ovulation date with an Early Detection Pregnancy Test.
If fertilization does not occur the egg dissolves after 24 hours. At this time your hormone levels will decrease and your uterine lining will begin to shed about 12-16 days from ovulation. This is menstruation (menstrual period) and brings us back to day 1 of your cycle. The journey then begins all over again.
The timing of ovulation is one of the most important things a woman should understand about her body since it is the determining factor in getting pregnant and preventing pregnancy.
How do I know if I’m ovulating?
There are several ways to figure out when ovulation happens:
- Menstrual cycle. Ovulation typically happens around day 14 of a 28-day menstrual cycle, counting from the first day of your period. But normal cycles can be as short as 21 daysTrusted Source in adults, or as long as 35 days. You’ll want to track your cycle over multiple months to learn its length. You’re likely to ovulate around the middle date of your cycle, give or take a few days.
- Body temperature. Your temperature rises slightly for a few days after ovulation takes place, by about 0.5 to 1.3°F (0.3 to 0.7°C) Trusted Source. You may be able to detect the change by taking your temperature every morning. Read more about Basal Body Temperature (BBT) charting.
- Vaginal discharge. There’s likely more of it around the time of ovulation. It’s usually more clear and more slippery.
- Using at-home trackers. Over-the-counter (OTC) options include ovulation predictor kits and fertility monitors.
Using several of these methods together is more likely to give you an accurate answer.
For example, body temperature charting is influenced by more than ovulation alone. It’s also affected by factors like illness or alcohol use.
If your period is irregular or absent, this may be a sign that you are not ovulating each month.
Irregular ovulation
If you track ovulation from one month to the next, you may notice that you’re either not ovulating regularly or, in some cases, not ovulating at all. This is a reason to speak with a doctor.
Things like stress or diet may affect the exact day of ovulation from month to month. There are also medical conditions, like polycystic ovary syndrome (PCOS) or thyroid disorders, that may make ovulation irregular or stop completely.
These conditions may cause other symptoms related to changes in hormone levels, including:
- increased growth of facial or body hair
- acne
- infertility, in some cases
How often should you have sex if you’re trying to conceive?
You only need to have sex once during your fertile window to achieve pregnancy. People who are actively trying to conceive may increase their chances by having sex every day or every other day during the fertile window.
For those using intrauterine insemination (IUI) to try to conceive, IUI is also conducted during the fertile window.
The best time Trusted Source to get pregnant is in the 2 days leading up to ovulation and the day of ovulation itself.
Is ovulation the only time you can become pregnant?
No. While the egg can only be fertilized in the 12 to 24 hours Trusted Source after it’s released, sperm can live in the reproductive tract under ideal conditions for about 5 days. So, if you have sex in the days leading up to ovulation or on the day of ovulation itself, you may become pregnant.
If you are not trying to get pregnant, using contraception is your safest option, at all times of your cycle.