How long does it take the egg to travel from the ovary to the uterus

In this article

• Inside the woman’s body: how an egg is hatched
• Inside the man’s body: how sperm are made
• What happens while you’re having sex
• What happens after sex
• How is the woman’s egg fertilised?
• Visit our community

Before you start trying, you may want to understand more about your fertility and learn exactly how you get pregnant. Conception is the moment when egg and sperm meet. It can take anything from 45 minutes to 12 hours for a sperm to reach your fallopian tubes, which is where conception usually happens. However, sperm can survive inside your body for up to seven days, so conception can happen at any point in the week after unprotected sex, if you’re ovulating.

Inside the woman’s body: how an egg is hatched

For women, the possibility of pregnancy begins in the ovaries. These are the two small, oval organs attached to either side of your womb (uterus). The ovaries are packed with eggs, which are made before you’re even born. Every baby girl is born with 1 million to 2 million eggs in her ovaries.

Many eggs begin dying off almost immediately and the rest steadily decrease in number and quality as you get older. When you start your periods, only about 400,000 to 500,000 eggs remain. From here on it’s normal to lose about 1000 eggs every month. By the age of 30, scientists calculate that about 72,000 viable eggs remain. After your mid-thirties egg numbers decline more rapidly.

You’ll probably release fewer than 500 eggs during your fertile years, between your first period and menopause. In countries such as the UK, the average age of menopause is about 51, but it can happen much earlier or later than this.

During each menstrual cycle, some time after your period, between three and 30 eggs start to mature in one of your ovaries. The ripest egg is then released, a process known as ovulation. The egg is quickly sucked up by the tulip-shaped opening of the nearest fallopian tube. There are two fallopian tubes, each about 10cm in length, which lead from the ovaries to the womb.

Ovulation is usually about 10 to 16 days before your next period starts. The exact time of ovulation depends on the length of your cycle. Several different hormones work together to control the length of your cycle, when your eggs ripen and the timing of ovulation. You can read more about these hormones in our article on the menstrual cycle.

Want to work out when you ovulate? Try out our ovulation calculator. Pinpointing the day of ovulation can help you work out your fertile window.

The average egg lives for up to 24 hours after release. It needs to be fertilised by a sperm within this time for a baby to be conceived. If your egg meets up with a healthy sperm on its way to the womb, the process of creating a new life begins. If not, the egg ends its journey at the womb and disintegrates.

If you’ve not conceived, the ovary stops making oestrogen and progesterone. These are the two hormones that would help maintain a pregnancy. When the levels of these hormones drop, the thickened lining of your womb is shed during your period. The remains of the unfertilised egg are shed at the same time.

Inside the man’s body: how sperm are made

Women’s bodies mature a single egg fully each month. Men’s bodies, however, are almost constantly at work, producing millions of microscopic sperm – about 100 million every day. The sole purpose of each sperm is to swim towards and penetrate an egg.

From start to finish it takes about 10 to 11 weeks to create a new sperm cell. The average sperm lives only a few weeks in a man’s body. Each ejaculation can set free up to 400 million sperm. This means that men have to make sperm continuously throughout their adult lives.

The same hormones that control ovulation in women stimulate the release of testosterone in men. Testosterone is the hormone responsible for producing sperm. Sperm production starts in the testicles, the two glands contained in the scrotal sac beneath the penis. The testicles hang outside the body because they are sensitive to temperature. To produce healthy sperm efficiently they have to stay at a balmy 34 degrees C. This is about three degrees cooler than normal body temperature. Once the man’s sperm is created, it’s stored in each testicle in the epididymis, a six-metre long coiled tube. Just before ejaculation the sperm is scooped up and mixed with semen.

Despite the millions of sperm that are produced and released in each ejaculation, only one can fertilise each egg. The sex of your baby depends on which type of sperm burrows into the egg first. Sperm with a Y chromosome will make a boy baby, and sperm with an X chromosome will make a girl. There are plenty of myths about how to conceive a boy or girl. Some claim to be backed by a bit of scientific evidence but, on the whole, it isn’t reliable and a child’s sex is determined randomly.

What happens while you’re having sex

In addition to all the fun, your bodies are building up tension that you hope will end in orgasm. Having an orgasm also has an important biological function. In men, an orgasm propels sperm-rich semen into the vagina and up towards the cervix at roughly 10 miles per hour. The force of ejaculation gives the sperm a good head start on their way to the egg.

The function of the female orgasm is less clear. Theories include that it strengthens the bond between partners, or that uterine contractions help the sperm along their way somehow. We know that a woman doesn’t need to orgasm for conception to happen, though. Uterine contractions happen even without you having an orgasm.

Many couples wonder if a particular sex position is best for conceiving. No one knows for sure. The most important thing about sex is that you’re both having a good time and you’re doing it often enough.

Not all women ovulate during the middle of their cycle or at the same time in their cycle every month. To improve your chances of conception, aim to have sex every two days or three days throughout your cycle. When you start trying for a baby, it’s recommended that you start taking folic acid. Learn more about the importance of folic acid while you’re trying and in early pregnancy.

What happens after sex

At this point you can’t do much except cross your fingers and hope that you conceive. While you and your partner enjoy a relaxing post-sex cuddle, a lot is going on inside your body. Those millions of sperm have begun their quest to find your egg, and it’s not an easy journey. The first obstacle may be your cervical mucus, which can seem like an impenetrable net on your non-fertile days. When you’re most fertile, however, it miraculously loosens up so the strongest swimmers can get through.

The sperm that survive still have a long road ahead. In all, they need to travel about 18cm from the cervix through the womb to the fallopian tubes. That’s the equivalent of a human being swimming 100 lengths of an Olympic swimming pool! The fastest swimmers may find the egg in as little as 45 minutes. It can take the slowest up to 12 hours. If the sperm don’t find an egg in the fallopian tubes at the time of intercourse, they can survive inside you for up to seven days. This means that if you ovulate within this time window you could still conceive.

The mortality rate for sperm is very high and only a few dozen ever make it to the egg. The rest get trapped, lost (they may head up the wrong fallopian tube) or die along the way. For the few that get near the egg, the race isn’t over. Each one has to work frantically to penetrate the egg’s outer shell and get inside before the others. The egg needs to be fertilised within 24 hours of its release. When the hardiest sperm of the bunch makes it through, the egg changes instantaneously to prevent any others getting in. It’s like a protective shield that clamps down over the egg at the exact moment the first sperm is safely inside.

How is the woman’s egg fertilised?

During fertilisation, the genetic material in the sperm and egg combine to create a new cell that will rapidly start dividing. This bundle of new cells is known as the blastocyst. It continues travelling down the fallopian tube towards the womb, a journey that can take another three days or so.

You are not actually pregnant until the blastocyst embryo has attached itself to the wall of your womb, where it will develop into a fetus and placenta. Occasionally, the blastocyst will implant somewhere other than the womb (usually in the fallopian tube). This is called an ectopic pregnancy, and it needs urgent medical attention. The pregnancy will not survive outside the womb and needs to be completely treated or removed.

It will be a couple of weeks until you miss a period and suspect that you’re pregnant. Once you’ve missed your period or noticed one of the other signs of pregnancy, a home pregnancy test will confirm it. If you’ve got a little one on the way, congratulations, and welcome to the start of another incredible journey.

My six-word conception story

Animated stories telling where, when, and even how the children of BabyCentre parents were conceived – using only six words! More preconception videos

Learn more

• What you need to know about stopping contraception.
• Learn the most common signs of infertility and when to seek medical advice.
• What is endometriosis?

Visit our community

Talk to others who are hoping to get pregnant by joining our Actively trying group.

References

CKS. 2017. Menopause. Clinical Knowledge Summaries. www.cks.nice.org.uk [Accessed May 2020]

Cox E, Takov V. 2019. Embryology, ovarian follicle development. StatPearls. www.ncbi.nlm.nih.gov [Accessed May 2020]

Deans A. 2018. Your new pregnancy bible. The experts’ guide to pregnancy and early parenthood. 4th edn. London: Hamlyn.

FPA. 2018. Bodyworks. Your guide to understanding reproduction. Family Planning Association. Derby: McCorquodale. www.sexwise.fpa.org.uk [Accessed May 2020]

Knudtson J, McLaughlin JE. 2019. Female reproductive endocrinology. MSD Manual, Professional Version. www.msdmanuals.com [Accessed May 2020]

Hirsch IH. 2019. Overview of male sexual function. www.msdmanuals.com [Accessed May 2020]

Kallen, A. 2020 How Many Eggs Are Women Born With? And Other Questions About Egg Supply. Healthline. www.healthline.com/ [Accessed July 2020]

Levin RJ. 2011. Can the controversy about the putative role of the human female orgasm in sperm transport be settled with our current physiological knowledge of coitus? J Sex Med 8(6): 1566-78. www.ncbi.nlm.nih.gov [Accessed May 2020]

Lodé T. 2020. A brief natural history of the orgasm. All Life 13: 34-44. www.tandfonline.com [Accessed May 2020]

NHS. 2018. Trying to get pregnant. Health A to Z. www.nhs.uk [Accessed May 2020]

NHS. 2019. How can I tell when I'm ovulating? Common Health Questions. www.nhs.uk [Accessed May 2020]

NICE. 2017. Fertility problems: assessment and treatment. National Institute for Health and Care Excellence. CG156. London: NICE. www.nice.org.uk [Accessed May 2020]

NICE. 2019. Pre-conception – advice and management. Clinical Knowledge Summaries. National Institute for Health and Care Excellence. cks.nice.org.uk [Accessed May 2020]

Rebar RW. 2019. Sperm disorders. MSD Manual, Professional Version. www.msdmanuals.com [Accessed May 2020]

Tiberi S, Scarpa B, Sartori N. 2018. A composite likelihood approach to predict the sex of the baby. Stat Methods Med Res 27: 3386-96. www.ncbi.nlm.nih.gov [Accessed May 2020]

Wallace WHB, Kelsey TW. 2010. Human ovarian reserve from conception to the menopause. PloS One 5(1): e8772. journals.plos.org [Accessed May 2020]

Wheatley J, Puts D. 2015. Evolutionary science of female orgasm. In Shackelford T, Hansen R (eds), The evolution of sexuality, pp 123-148. New York: Springer. www.researchgate.net [Accessed May 2020]

How long after ovulation does the egg reach the uterus?

How long does it take for egg to attach to uterus?

How long does it take the egg to travel from the ovary to the fallopian tube?

How long does it take the sperm to travel from the ovary to the uterus?