Pregnant and ovulation

Fertilization, Process & When It Happens

How does conception occur?

Conception (or fertilization) is when sperm and an egg join together. It’s one of the many steps that happen to create a pregnancy.

Conception is closely related to a person’s menstrual cycle. A menstrual cycle describes the sequence of events that occur within your body as it prepares for the possibility of pregnancy each month. Women or people assigned female at birth (AFAB) ovulate during their menstrual cycle. Ovulation is when your ovary releases an egg for fertilization. Tiny finger-like structures called fimbriae help guide the egg through your fallopian tubes towards your uterus. During this journey through your fallopian tubes, an egg can be fertilized by sperm.

Sperm production begins in the testicles of men or people assigned male at birth (AMAB). During ejaculation, millions of sperm cells are set free with the sole purpose of finding an egg to fertilize. When you have unprotected sex, sperm cells swim up through your vagina and into your fallopian tubes. Millions of sperm battle to reach and penetrate the egg, but only one breaks through the egg's outer layer to fertilize it. If sperm doesn't fertilize an egg, the egg dissolves.

If a sperm is successful on its quest to fertilize an egg, the now fertilized egg (called a zygote) continues to move down your fallopian tube, dividing into two cells, then four cells, then more cells. About a week after the sperm has fertilized the egg, the zygote has traveled to your uterus. It's now a growing cluster of about 100 cells called a blastocyst.

The blastocyst then attaches itself to the lining of your uterus (the endometrium). This attachment process is called implantation. However, just because conception occurs doesn't mean implantation will. Sometimes implantation doesn't happen, and you pass the fertilized egg in your next menstrual period.

If implantation happens, the cells continue to divide — some cells develop into your baby and others form the placenta. You begin to release hormones that tell your body a baby is growing inside your uterus. These hormones also signal the uterus to maintain its lining rather than shed it. This means you won't get your menstrual period, which may be the first way you know you’re pregnant.

Timeline of getting pregnant

You calculate your menstrual cycle from the first day of menstrual bleeding to the start of the next first day of menstrual bleeding. Most menstrual cycles are around 28 days long. The exact time you ovulate varies depending on how long your menstrual cycle is.

The process of getting pregnant in a 28-day menstrual cycle is:

Day one: First day of your period.
Around day 14: Ovulation occurs.
Within 24 hours of ovulation: Sperm fertilizes an egg (conception occurs).
About six days after fertilization: The fertilized egg implants into your uterine lining.
Around day 21: If conception and implantation occurred during this menstrual cycle, you're pregnant. However, getting a positive pregnancy test may take another five to seven days.

Conception and a positive pregnancy test

After conception, a fertilized egg travels through your fallopian tubes to your uterus. The fertilized egg (called an embryo) implants (attaches) into the wall of your uterus. This triggers the placenta to form. Your placenta begins producing and releasing human chorionic gonadotropin (hCG) into your blood and pee. HCG can be found in a person’s blood around 11 days after conception. It takes slightly longer for hCG to show up on at-home pregnancy tests (that measure hCG in pee).

What are my chances of conceiving?

Just because an egg and sperm are near each other doesn't mean conception will happen. In general, conception only happens 25% to 30% of the time. This percentage decreases once you reach age 35.

How does conception work with IVF?

Conception still works the same way — sperm must fertilize an egg. However, with in vitro fertilization (IVF), sperm fertilizes an egg in a lab. An egg, either from the intended parent or a donor, is mixed with sperm from a parent or donor. Conception happens when sperm fertilizes the egg.

Once conception occurs, your provider places the created embryo inside the uterus that will carry the pregnancy for implantation.

When does conception happen?

Conception occurs between 12 and 24 hours after ovulation. It’s sometimes hard to pinpoint ovulation, so using ovulation predictor kits or tracking your menstrual cycle on a calendar may be helpful. The two biggest factors in conception are:

The timing of sexual intercourse with ovulation.
Egg and sperm health.

When should I have sex to conceive?

Conception can happen after unprotected sex as early as five days before ovulation. This is because some sperm can live that long inside female reproductive organs.

If you’re trying to conceive, the best times to have sex are:

In the three days before ovulation: In this scenario, sperm will be “waiting” for the egg to come down the fallopian tube.
At ovulation or within 24 hours of ovulating: Your egg lives for only 24 hours, so if you have unprotected sex during this time, your egg may end up “waiting” for sperm to reach it, or they may run into each other in your fallopian tubes.

Where does conception happen?

Conception typically happens in your fallopian tubes. This is where an egg goes after it leaves your ovary and where sperm wait for an egg. In some cases, fertilization can happen in your uterus once your egg has left your fallopian tubes.

What things prevent conception from happening?

Certain health conditions may affect your ability to conceive. Just because the sperm and egg meet doesn't mean fertilization will occur. Some of the most common factors are:

Anovulation (you’re not ovulating).
Low sperm count or issues with sperm motility (how sperm move).
A blockage in the testicles, ovaries or fallopian tubes.
Decreasing amount of quality eggs and quality sperm (usually related to aging).

Can you feel conception?

Not usually. You may notice signs that you've ovulated, such as changes in your cervical mucus or basal body temperature. However, most people don't feel fertilization. You may feel a dull ache or experience light spotting several days after conception. This could be from the fertilized egg implanting in your uterus.

When do you start feeling pregnant?

How long it takes to “feel” pregnant varies. Some people may start to feel pregnant shortly after conception, while others don’t have any pregnancy symptoms for weeks after a positive test.

Common signs of pregnancy are:

A missed period.
Frequent urination.
Feeling tired.
Nausea.
Sore or swollen breasts.
Spotting (light vaginal bleeding).
Headaches.
Mood swings.

Take a home pregnancy test if you have any of the above symptoms and think there’s a chance you’re pregnant. Your healthcare provider can order a blood test to confirm pregnancy.

Are conception and fertilization the same?

Conception and fertilization are two different parts (or steps) of the same process. Conception is the first step, where an egg and sperm join. Fertilization is another step, where the joined sperm and egg plant like a seed into your uterine lining.

How long after conception will my pregnancy test be positive?

It can take between 11 and 14 days after conception to get a positive pregnancy test. At-home pregnancy tests check for human chorionic gonadotropin (hCG), a hormone released by the placenta. Your pee must have enough hCG to get a positive pregnancy test. However, your healthcare provider can check for hCG in your blood sooner — around 10 days after conception.

A note from Cleveland Clinic

Conception is when sperm fertilizes an egg. It’s one of the many critical steps in getting pregnant. Conceiving a child is a complex process dependent on lots of factors. Being unable to conceive is a common problem, and there are lots of resources available to help you. Contact your healthcare provider if you’re struggling with conceiving. They can explain the process and identify any issues preventing conception and pregnancy.

Facts to Help You Get Pregnant

Reviewed by Brunilda Nazario, MD on November 15, 2021

When you know your menstrual cycle, you improve your chances of getting pregnant. The first phase starts with the first day of bleeding during your period. Your body releases hormones, like follicle-stimulating hormone (FSH), that make the eggs inside your ovaries grow. Between days 2 and 14, those hormones also help thicken the lining of your uterus to get ready for a fertilized egg. This is called the follicular stage.

The average menstrual cycle is 28-35 days. Ovulation usually happens between days 11 and 21 of your cycle. A hormone called luteinizing hormone (LH) surges, triggering the release of the egg that's most ripe. At the same time, your cervical mucus becomes more slippery to help sperm make their way to the egg.

Women are born with about 1 million to 2 million eggs but release only 300 to 400 through ovulation during their lifetimes. Usually, you release just one each month. The egg travels along one of the two fallopian tubes that connect your ovaries to your uterus. If the timing is right, sperm may fertilize it on its way to the uterus. If fertilization doesn't happen within 24 hours of the egg leaving the ovary, the egg dissolves. Sperm can live for about 3 to 5 days, so knowing when you are ovulating can help you and your partner plan sex for when you're most likely to conceive.

Generally, the best chance of pregnancy is when sex happens 1-2 days before ovulation. If you have a regular 28-day cycle, count back 14 days from when you expect your next period to start. Plan on having sex every other day around that time -- say, days 12 and 14. Your cycle may be longer or shorter, so an online ovulation calculator or over-the-counter ovulation and fertility kits can help you figure out the most likely day.

After your body releases an egg, the hormone progesterone kicks in to build and maintain the lining of the uterus. It makes your body temperature go up slightly. So taking your temperature with a basal thermometer every morning before you get out of bed can help you figure out if you ovulated. You can buy these thermometers at the drugstore. They're inexpensive, but they aren't as accurate as other ways of monitoring fertility.

A surge in LH triggers your ovaries to release an egg. The surge usually happens 36 hours before the egg is released. Ovulation kits and fertility monitoring kits measure LH levels and other hormones to help you pinpoint the day of ovulation. These kits use hormones or come as wearable devices and are convenient and highly accurate. You may want to test 1-2 days before you expect the surge so you can note the rise in LH.

During the second half of your menstrual cycle, the hormone progesterone kicks in to help prepare the lining of your uterus for a fertilized egg. If the egg isn't fertilized and doesn't implant, it disintegrates, progesterone levels fall, and about 12 to 16 days later, the egg -- along with blood and tissues from the lining of the uterus -- is shed from the body. That process is menstruation. It usually lasts 3 to 7 days.

If you're overweight or obese, losing weight can boost your chances of getting pregnant. A study found that women whose body mass index (BMI) was above normal took twice as long to get pregnant as those with a normal BMI. But a drop in weight of 5%-10% can dramatically improve ovulation and pregnancy rates. Obesity can also cause infertility and low testosterone in men. Being significantly underweight can also lead to infertility.

Fertility goes down with age, especially after the mid-30s. It also lowers the chances that fertility treatments will be successful. Experts say you should talk to your doctor if you're under 35 and have been trying to conceive for more than 12 months, or over 35 and have been trying for more than 6 months.

Studies show that sperm count and sperm movement decrease as men age, as does sexual function. But there isn't a cutoff age that makes a man too old to father a child. One study found that it took men age 45 or older longer to get a woman pregnant once the couple started trying. If your partner is older, you may want to talk to your doctor about ways to boost your chances.

Manage stress.
Avoid alcohol and tobacco.
Maintain a proper weight.
Eat a diet high in zinc (found in meat, whole grains, seafood, and eggs), selenium (meat, seafood, mushroom, cereals, and Brazil nuts), and vitamin E.
Keep the testicles cool -- no long, hot baths, hot tubs, or saunas, which can reduce the number of sperm.

A number of things can cause infertility. The first step is for your doctor to check out you and your partner. Infertility treatments can include fertility drugs, to stimulate ovulation, and in vitro fertilization, which involves removing eggs from the ovaries, fertilizing them, and then implanting them into the uterus.

Home pregnancy tests check your urine for the "pregnancy hormone," called hCG, that your body makes once a fertilized egg implants in your uterus. Some of these tests may be able to tell if you're pregnant around the time of your missed period.

You miss a period.
You need to pee often.
You get tired easily.
You're nauseated in the morning -- or all day.
Your breasts become larger and more tender.

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The National Infertility Association, Resolve.org: "The Menstrual Cycle," "Tracking Most Fertile Time," "The Impact of Environmental Factors, Body Weight & Exercise on Fertility."
American Pregnancy Association: "Understanding Ovulation," "Ovulation Calculator: How to Track Ovulation," "OV-Watch Fertility Predictor," "Pre-Conception Health for Men."
UptoDate.com: "Evaluation of the Menstrual Cycle and Timing of Ovulation."
The Jones Institute for Reproductive Medicine: "Fertility Tests -- Ovulation," "In Vitro Fertilization (IVF)," "Ovulation Induction (OI)."
News release, National Institutes of Health.
American Society for Reproductive Medicine: "Patient's Fact Sheet: Weight and Fertility," Age and Fertility: A Guide for Patients."
Womenshealth.gov: "Healthy Pregnancy: Trying to Conceive," "Pregnancy Tests."
Eskenazi, B. Human Reproduction, February 2003; vol 18: pp 447-454.
Hassan, M. Fertility and Sterility, June 2003; vol 79: pp 1520-1527.
Mayo Clinic: "Symptoms of pregnancy: What happens first."

Ovulation and pregnancy | Huggies® Official Website

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How does ovulation and fertilization occur?

In the first phase of the menstrual cycle, follicle maturation begins in one of the ovaries. This small vesicle consists of an ovum enclosed in a "shell" of connective tissue. The follicle grows from 1 mm to 12–16 mm ¹ and then bursts, releasing the egg into the fallopian tube. This moment is called ovulation.

What happens after ovulation? The egg becomes available for fertilization. For this to happen, there must be enough sperm in the fallopian tube. Contrary to popular belief, the winner will not be the most agile of them all. The ovum is surrounded by a special membrane called the "radiant crown" ² (sounds very nice, doesn't it?). First, many fighters will die trying to destroy the protective shell, and only then one lucky one will get inside and fertilize the egg.

When does pregnancy occur? Right after ovulation?

The period in which a woman can become pregnant does not last very long: the egg cell lives only about 24 hours ³ . This gives us the answer to the question of how long after ovulation conception occurs - at any point in this short period. In particular, fertilization can happen almost immediately if the spermatozoa made their way into the fallopian tube even before the egg is released from the follicle.

Some women report that they did not become pregnant on the day of ovulation, but earlier or later. This is impossible in principle, and they are wrong - it's just that the actual date of this event may not coincide with the calculated one. It is normal if ovulation happened a day or two earlier or later than the plan, and under certain conditions (hormonal changes, stress, and others), it can go beyond this. More details in this article.

So how do you calculate ovulation?

Pregnancy begins after ovulation and fertilization of the egg by sperm. It's up to the small thing - to understand when this important event will happen. Take a calendar and look at our drawing. With it, you can calculate the approximate date of ovulation. But remember, this is just a prediction, and that's why we've drawn high, medium, and low pregnancy probability areas around the central day.

Do not try to get pregnant exactly at ovulation. It is better to cover the entire period of high probability with a “queue”. Start having sex for pregnancy 4 days before the planned date and do it every other day: 4th day before, 2nd day before, day of ovulation, 2nd day after, 4th day after. This will greatly increase your chances of success.

Approximate menstrual cycle schedule. Calculations are given for cycles with a duration of 25 to 31 days.

The ideal menstrual cycle is 28 days. In many articles on conception and ovulation, all the reasoning is built around this textbook case. Indeed, it is very convenient - ovulation in it occurs on the 14th day, dividing the cycle into two equal halves. Life is different from the ideal: the duration of the cycle for different women varies, but usually ranges from 25 to 31 days ⁴ .

Most likely, you will find your case in this figure, but if your cycle is shorter or longer, there is nothing strange in this - the duration is from 21 to 35 days ⁵. The following knowledge will help calculate the day of ovulation: with a change in the length of the cycle, its first part usually decreases or grows, while the second remains unchanged and is always about two weeks. Set aside 14 days back from the planned first day of menstruation - get the approximate day of ovulation.

There are many more signs of ovulation that you can check out in this article.

In terms of conception, the menstrual cycle can be divided into the following phases (shown in the figure):

Menstruation. Sex during this period can only lead to conception under very unusual circumstances. For now, relax - auspicious days ahead.
From the end of menstruation to the 6th day before the planned ovulation. The probability of conception at this time is minimal. Most likely, the egg has not only not left the ovary, but has not even matured yet.
5 to 3 days before the estimated ovulation date. The chance of getting pregnant increases, and there are two reasons for this. Firstly, the real day of ovulation does not always coincide with the calculated one. Secondly, spermatozoa know how to wait. Most of them will die in the vagina within a couple of hours - its acidic environment fights well not only with bacteria. However, those that can penetrate the uterus are able to live up to three, sometimes up to five days ⁶ .
Planned day of ovulation plus or minus two days. During this period, a woman is most fertile. Given the lifespan of the egg and sperm, sex these days is highly likely to lead to pregnancy. Of course, if there are no factors that can interfere with this.
3 to 4 days after estimated ovulation date. The chance of getting pregnant is decreasing, but still remains. Do you remember that calculating the day of ovulation is not a very exact science? So anything is possible.
From the 5th day after the planned ovulation until the end of the cycle. Do not seriously expect that you will be able to conceive these days, have sex just for fun. If you have tried to get pregnant on your fertile days, you may have already conceived!

What should be the feeling after ovulation?

During the menstrual cycle, there is only one period in which a woman feels the changes taking place in her body. This is menstruation itself, and the sensations from it are very familiar to you. All other phases of the cycle are "asymptomatic".

The answer to the question of how to understand that ovulation was successful is prosaic: no way. The woman's body simply does not have a mechanism that would tell the brain about it. So, if you woke up with the certainty that today is that very day, these are just mind games that frolicked in a dream with the thought you desired about the joy of motherhood. Although, coincidences also happen :)

Even if the pregnancy has not even begun, but now you need to prepare for childbirth - study useful articles and look for courses for expectant mothers. Take the test and find out how well you are ready for childbirth and motherhood.

When will signs of pregnancy appear after ovulation and conception?

Reliable - not soon. A regular pregnancy test will show two cherished strips only after a delay, a test with increased sensitivity or laboratory analysis - 3-4 days earlier. The final confirmation with the help of ultrasound will have to wait another couple of weeks.

Do not expect pregnancy symptoms immediately after ovulation. While the fertilized egg slowly gets from the fallopian tube to its destination, almost no changes occur in the body. The first signs of pregnancy will appear only 6-10 days after ovulation, when the embryo attaches to the wall of the uterus ⁷ . And they will be almost invisible:

Change in basal body temperature. If you have been measuring your basal temperature all this time, you will notice a slight drop on the chart, and then a rise to a new, higher level.
Implantation bleeding. In the process of attaching the embryo to the wall of the uterus, the endometrium is damaged - its inner mucosa. In this case, the expectant mother may notice slight spotting.
Pain or cramps in the lower abdomen. Along with bleeding, mild pain may come. Therefore, women often attribute these first signs of pregnancy to early menstruation.

Why did not conception occur after ovulation?

You tried to get pregnant, but your next period started right on time. Why did it happen? Only your doctor can accurately answer this question, but we will list some likely causes.

Anovulatory cycle. Some menstrual cycles do not ovulate and this is perfectly normal ⁸ . They are called anovulatory and are needed by the body so that it can take a little break from the constant preparation for pregnancy. During the year, a woman experiences 1–2 anovulatory cycles.
Gynecological diseases. Sometimes conception after ovulation does not occur because the woman has gynecological diseases. Inflammation of the ovaries, blockage of the fallopian tubes, and some other conditions can significantly reduce the likelihood of pregnancy, and under certain conditions, even make conception impossible. A gynecologist can identify such diseases and prescribe treatment.
Immune or autoimmune reactions. Spermatozoa are very unusual cells. They contain only half of the chromosome set, and from the point of view of the immune system, they look like mutants. Everything is so bad that nature even had to collect them in special refrigerated bags and hang them outside the man's body. In some cases, the immune mechanisms of a woman can deal with spermatozoa at the time of passage of the cervix ⁹ . Autoimmune reactions also occur when a man's body destroys them. If the doctor considers that this may be the reason for unsuccessful attempts at conception, he will prescribe tests for both the expectant mother and the future dad.
Poor semen quality. After intercourse, spermatozoa will have to overcome the champion's obstacle course - survive in the aggressive environment of the vagina, break through the cervical mucus in the cervix, get to the right fallopian tube, destroy the protection of the egg. If the spermatozoa of the future dad are not very active, they can go the distance before conception. To exclude this cause, it is necessary to make a spermogram.

When conception occurs after ovulation, future parents take it for granted. If pregnancy does not occur, they often begin to panic and think with horror that they will never hear ringing children's laughter and light steps of tiny legs in their house. Drive unconstructive thoughts away - many couples were able to conceive far from the first time. Try again next month. We believe you will definitely succeed!

Links to sources:

Ovaries: follicles, growth and development disorders.
Pansky, Ben (1982), "Chapter 12: Fertilization", Review of MEDICAL EMBRYOLOGY.
Depares J, Ryder RE, Walker SM, Scanlon MF, Norman CM (1986). Ovarian ultrasonography highlights precision of symptoms of ovulation as markers of ovulation. Br Med J (Clin Res Ed). 292 (6535): 1562.
Chiazze L, Brayer FT, Macisco JJ, Parker MP, Duffy BJ (February 1968). "The length and variability of the human menstrual cycle". JAMA. 203(6): 377–80.
"Menstruation and the menstrual cycle fact sheet". Office of Women's Health, USA. December 23, 2014.
Clubb E. Natural methods of family planning. JR Soc Health. 1986 Aug;106(4):121-6.
Wilcox AJ, Baird DD, Weinberg CR (1999). "Time of implantation of the Conceptus and loss of pregnancy". New England Journal of Medicine. 340(23): 1796–1799.
Anovulatory Cycle: Symptoms and Detection.
What Are Antisperm Antibodies?

Fomin's clinic — a network of multidisciplinary clinics

Today's world is full of information: literally with one click, each of us can open the Universe and learn everything - from string theory to concert posters for the next week. It is all the more interesting that, having unlimited access to knowledge, we still live in myths - and sometimes they arise, including thanks to the Internet, replicating untruth and absurdity.

We have prepared for you a short “blitz” of six questions or myths about pregnancy and conception, so that you are fully equipped and do not believe the tales on the Internet.

Well... not exactly. Firstly, the idea of a “full examination” is a clear exaggeration, because there is no single list of tests that an expectant mother needs to pass. Ideally, visit a doctor three months before the end of contraception, get tested for STIs and antibodies to rubella. If additional examinations are required, you will be individually prescribed everything you need - including, probably, vaccinations that should be “updated”. As for alcohol and smoking, they are really contraindicated at the stage of pregnancy planning, so if you have these addictions, you will have to give them up. However, it should be remembered that smoking cessation applies to both electronic cigarettes and “passive smoking”, which can lead to dangerous consequences for the fetus.

Spoiler: no big deal. Do not panic and blame yourself for all mortal sins because of a glass of wine. With the recognized insecurity of alcohol, scientists have proven that a woman drinking 1-2 servings a couple of times a week should not harm the unborn child. For men, the allowable figures are slightly higher - 3-4 doses of alcohol per week. The main thing is to know the measure and not to overdo it.

There is, of course, a simplified formula for calculating the estimated due date: plus 7 days and minus 3 months from the date of the last period, but to be honest, it doesn’t work like that: the fact is that it is very difficult to “program” pregnancy and make sure that the child is born when you want. If you have a plan and are going to stick to it, be prepared for the fact that things can go wrong, if only because:

the duration of pregnancy is not 40 weeks, but 37-42 weeks, which means that you can easily fall into a five-week “loop”, which will reduce the chances of fulfilling the plan to zero;

with regular sex, the probability of conception is not 1 time per month (exactly when you guessed it), but 1 time per year.

Nothing is impossible... However, it is worth clarifying the question a little: you can get pregnant only during ovulation (more precisely, shortly after it), but you can have sex, which will lead to a long-awaited pregnancy, on different days. Of course, on the days of menstruation, the probability is lower than on the days that precede ovulation, but on none of the days of the menstrual cycle this probability is not zero.

Let's just say that several attempts a day is a bad idea. Why? At least because ejaculation more than once a day worsens the quality of sperm, as a maximum - such perseverance and zeal can create tension in the relationship of partners. Doctors advise to have sex every 2-3 days throughout the cycle, and not try to guess the moment and throw all your strength into this short period.

Planning the sex of a child is an extremely prolific topic for myth-makers. Some believe that with the help of a special table that takes into account such indicators as the age of the father and mother, the month of conception, it is possible to accurately calculate the sex of the child. This "method" is anti-scientific and has nothing to do with reality.

Another myth is that you have to get pregnant on the day you ovulate to have a boy. Previously, scientists really believed that X and Y spermatozoa differ from each other (Y are faster), and the sex of the child is formed due to the first one that broke through the defenses of the female egg. If you want to conceive a boy, you need to have sex on the day of ovulation so that the Y-sperms responsible for the "male sex" have more time to get to the egg located farthest from the entrance to the uterus.

However, this myth does not stand up to criticism: the fact is that there is no difference between the X and Y chromosomes, which means that the sex of the child does not depend on which of the sperm reaches the egg first.