By Zaira Salvador BSc, MSc (embryologist) and Óscar Oviedo Moreno MD (gynecologist).
Last Update: 09/21/2018

Ovulation is the process whereby a mature egg cell is released after developing in the woman’s ovary.

It is a crucial phase of the menstrual cycle, which is triggered thanks to the action of female sex hormones.

During ovulation, the woman is on her most fertile days (fertile window). In other words, it is at this point when unprotected sexual intercourse is most likely to cause a pregnancy.

The different sections of this article have been assembled into the following table of contents.

Definition

Ovulation translates into the most fertile days of a woman. The ovary releases a mature egg cell to the Fallopian tube, where it will stay until a sperm cell reaches and fertilizes, thereby creating an embryo.

To this end, an ovarian follicle containing an egg cell has to grow during the follicular phase of the menstrual cycle. When the follicle reaches the adequate size, the action of LH causes it to burst and release an egg.

Ovulation takes place thanks to the luteinizing hormone (LH), which increases its levels in order to trigger the process. It is known as LH surge.

After ovulation, the mature egg cell releases has an average lifespan of 24 hours. If fertilization doesn’t occur during this timeframe, the egg cell will degenerate eventually. The woman’s fertile days come to their end after this, and the couple would have to wait until the next cycle to try to conceive again.

On the other hand, in case fertilization takes place and results in an embryo, it will continue its journey toward the uterus, where it will attach and mark the beginning of a new pregnancy.

In the second phase of the menstrual cycle, the ruptured ovarian follicle turns into the corpus luteum, which is responsible for estrogen and progesterone production.

You may also enjoy some further information reading this: The Four Phases of the Menstrual Cycle.

Date of ovulation

In women with regular menstrual cycles, ovulation is expected to occur at some point halfway through the menstrual cycle. Simply put, in 28-day cycles, ovulation happens on day 14.

As explained above, the menstrual cycle is regulated by sex hormones. FSH and LH, produced by the pituitary gland, are the most important ones. They reach their peak level during ovulation, and for this reason are good indicators of the most fertile days, especially LH.

Alterations in the levels of FSH and LH could lead to anovulation or other menstural irregularities.

Both women who are trying to conceive and those who want to prevent it are interested in learning about their fertile days. This allows them to get the timing right.

The following are the most commonly used methods to predict the day of ovulation:

Ovulation calculator & calendar

First of all, it is necessary that you know the average length of your menstrual cycles, keeping in mind that they start at the beginning of your period and end with the start of the next period.

As mentioned above, ovulation occurs on day 14 approximately in women with 28-day menstrual cycles. The fertile window covers from day 12 until day 16 (periovulatory phase).

In women with shorter or longer cycles, the best way to calculate the ovulation day would be by subtracting 15 days to the expected date for the next period. The days prior to and after ovulation should be taken into account as well.

The fertile window covers five days because sperms are expected to be able to survive inside the female reproductive system for about 72 hours. So, even if sexual intercourse took place before ovulation, there would be chances of getting pregnant, too.

Read more: How Do Online Fertility Calculators Work?

Ovulation Predictor Kits (OPKs)

This method is more accurate than ovulation calculator. For this reason, it is commonly used by women who are trying to get pregnant actively.

OPKs work by measuring the levels of LH in urine and can be purchased at a pharmacy or ordered online.

LH levels start rising exponentially between 36 to 24 hours before ovulation, when they reach their peak (LH surge), and start diminishing again.

Getting a positive result on an OPK means that you are on your fertile days. The main advantage in comparison with the calendar method is that OPKs are able to predict ovulation even in women with irregular cycles.

Signs & symptoms

Certain signs and symptoms in the woman’s body may indicate that ovulation is taking place. The following are the most common ones:

BBT stays high
Basal Body Temperature (BBT) increases from 0.2 to 0.5 °C during ovulation, due to the increase in the levels of progesterone after releasing an egg.
Increased vaginal discharge
It changes its consistency and increases its amount. It becomes more elastic and jelly-like to allow the passage of the sperm through the cervix. It is due to an increase in the levels of estrogens.
Cervix changes
It will rise and its texture become softer. Also, it relax to allow the cervical opening to open up enough as to allow the passage of sperm.
Pain
Cramps or discomfort in the lower abdomen due to a ruptured ovarian follicle.

More often than not, these changes go unnoticed by the woman, but could be detected by paying attention to your body signs.

FAQs from users

Can alterations in the cervical mucus lead to female infertility?

By Óscar Oviedo Moreno MD (gynecologist).

Yes, alterations in the cervical mucus can are a common cause of female infertility. The cervical mucus is a secretion produced before ovulation and it disappears after the woman ovulates. It has a sticky texture, and its mission is to pave the way for sperms toward the tubes. It is, in fact, a good indicator of female fertility.

Does fever affect ovulation?

By Zaira Salvador BSc, MSc (embryologist).

No, it doesn’t. However, in women who use the basal body temperature method to track their ovulation, a fever will make the temperature readings inaccurate, thereby making it harder to determine her most fertile days. But fever won’t screw up any progress you and your partner have already made.

Can ovulation day vary each month?

By Zaira Salvador BSc, MSc (embryologist).

Yes, it is possible. Menstrual cycles are subject to many factors that occur to women throughout the cycle, so it’s only logical that ovulation days vary from month to month. In women with 28 to 32 day menstrual cycles, ovulation is expected to occur between days 11 to 21.

When do women ovulate?

By Zaira Salvador BSc, MSc (embryologist).

In women with a normal 28-day menstrual period, the most fertile period, that is, ovulation occurs 14 days after the first day of the last menstruation. Nonetheless, the days before and after this date are considered to be fertile, which means that the woman could get pregnant as well.

When do you ovulate after an abortion?

By Zaira Salvador BSc, MSc (embryologist).

Abortions that are carried out without complications have no negative impact on the woman’s fertility as a general rule. This means that your next ovulation is expected to occur about 2 weeks after the induced abortion.

Can you get pregnant not during ovulation?

By Zaira Salvador BSc, MSc (embryologist).

Unless you have irregular menstrual cycles, it is highly unlikely. There are only 6 days during a woman’s cycle when she can actually get pregnant, keeping in mind that sperm can live for up to 5 days in the woman’s body, and the egg for only 12-24 hours after being released.

Can sperm meet egg before ovulation?

By Zaira Salvador BSc, MSc (embryologist).

Yes. If a couple has intercourse as early as six days before ovulation, there is also a change of pregnancy, but it’s much smaller than during ovulation.

Can you release an egg during your period?

By Zaira Salvador BSc, MSc (embryologist).

Yes, it is possible in women with shorter cycles or highly irregular cycles. In such cases, unprotected sex during your period could lead to pregnancy.

Do you release an egg every time you ovulate?

By Zaira Salvador BSc, MSc (embryologist).

Yes. If the body doesn’t release an egg during a woman’s cycle, it is known as anovulatory cycle. In other words, that ovulation is not occurring. If a woman doesn’t ovulate or release an egg, she should not have any bleeding at all.

Do you release an egg on birth control?

By Zaira Salvador BSc, MSc (embryologist).

It depends on the type of birth control method used. If you use a hormonal type of contraceptive, then the answer is no: they work by inhibiting ovulation. Birth control pills and other hormonal methods contain synthetic forms of estrogen and progestin, which are used to alter the normal functioning of the cycle in order to prevent ovulation.

Other forms of birth control, such as the copper IUD and condoms, don’t contain hormones, hence their name barrier methods. They work by blocking the pathway of sperm toward the egg.

Is the date of ovulation the date of conception?

By Zaira Salvador BSc, MSc (embryologist).

No. Conception can occur as early as within 24 hours of ovulation. Also, and keeping in mind that sperm can live inside a woman’s body for up to three days, conception can happen 3 days after sexual intercourse, depending on the date of ovulation.

Is it possible to ovulate from both ovaries?

By Zaira Salvador BSc, MSc (embryologist).

Normally, the ovaries take alternate turns in releasing an egg, but sometimes both ovaries can release an egg at the same time. If fertilization occurs in both, the woman will get pregnant with non-identical twins.

Does ovulation make you more attractive?

By Zaira Salvador BSc, MSc (embryologist).

Yes, kind of. In fact, men can actually sense when a woman is ovulating due to the effect of what is known as female pheromones, along with an increased level of testosterone. It is believed that women send olfactory clues during ovulation to be more attractive to men.

Is it possible to ovulate twice in a month?

By Zaira Salvador BSc, MSc (embryologist).

No, it is almost impossible. However, as explained earlier, you can release two or more eggs during the same 24-hour ovulation period.

What is the best day of ovulation to conceive a boy?

By Zaira Salvador BSc, MSc (embryologist).

There is no possible way to predict gender before conception. The gender of the unborn child will be determined by the sperm cell randomly.

Recommended for you: What’s the Function of a Sperm Cell? – Definition & Structure.

Suggested for you

Oftentimes, when a woman has shorter or irregular menstrual cycles, her fertile days take place very close to her menstruation. Check out this for information: Is It Actually Possible for You to Get Pregnant While on your Period?

As explained above, hormonal alterations can lead to alterations in the menstrual cycle and affect ovulation. Get more info by clicking the following link: Female Infertility Due to Ovarian Endocrine Factor.

Sharing is caring

Our editors have made great efforts to create this content for you. By sharing this post, you are helping us to keep ourselves motivated to work even harder.

References

Chiazze L Jr Brayer F T Macisco J J Jr Parker M P Duffy B J 1968 The Length and Variability of the Human Menstrual Cycle JAMA, 203 (6) pp 377-380.

Fluhmann C F 1934 The Length of the human menstrual cycle. Department of obstetrics and gynecology American Journal of Obstetrics and Gynecology, 2 (1) pp 73-78.

Haroun HSW. Reproductive cycles in females. MOJ Women’s Health. 2016;2(2):62‒64.

Hummel, T., Gollisch, R., Wildt, G., and Kobal, G. (1991). Changes in olfactory perception during the menstrual cycle. Experentia, 47, 712-715.

Vollman R F 1956 The Degree of Variability of the Length of the Menstrual Cycle in Correlation with Age of Woman Gynaecologia 142 (5): 310–314.

Wilcox AJ, Weinberg CR, Baird DB. Timing of intercourse in relation to ovulation: effects on the probability of conception, survival of the pregnancy and sex of the baby. N Engl J Med 1995;333:1517– 1521.

Read more

Authors and contributors

 Zaira Salvador
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia (UPV). Embryologist specializing in Assisted Procreation, with a Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). More information
License: 3185-CV
 Óscar Oviedo Moreno
Bachelor's Degree in Medicine & Surgery from the University of Caldas (Colombia). Specialist in Internal Medicine by the Pontificia Universidad Javeriana of Bogotá. Degree standardized in Spain in 2003. Specialist in Gynecology & Obstetrics from the Complutense University of Madrid, with residence at Hospital Clínico Universitario San Carlos de Madrid. Expert in Reproductive Medicine and Certification in Obstetric-Gynecologic Ultrasound (levels I, II and III). More information
License: 282858310
Follow us on social media

Find the latest news on assisted reproduction in our channels.