How does pregnancy happen from intercourse?
Pregnancy has a lot to do with the menstrual cycle and the ovaries. The female reproductive system typically has two ovaries, one on each side of the body. Each month a group of eggs, or ova, develops inside the ovaries.
Around two weeks before the next period starts, one egg is released from a part of the ovary called a follicle. This process is called ovulation. At that point, the egg begins its journey down the uterine tubes towards the uterus (also known as the womb). This single egg stays in one of the uterine tubes for around 12–24 hours — this is when the egg can become fertilized by a single sperm.
Sperm is part of the semen that is released by the penis during ejaculation, which occurs as part of an orgasm. Sometimes semen is referred to as “come” or “cum.” Semen is produced in the testicles. The semen of an average man contains 15–200 million sperm per milliliter (or from 39 to up to 1000 million per ejaculation). The greater the volume of the ejaculate is, the higher the amount of sperm available to fertilize an egg will be. The World Health Organization suggests that a lower-limit sperm number among fertile men is between 33–46 million per ejaculation.
Fertilization happens when sperm comes in contact with an egg. This can happen through sexual intercourse, when the penis ejaculates sperm into the vagina, or through other methods such as IUI and IVF.
In case of intercourse, during arousal, the penis becomes long and hard, allowing it to be inserted into the vagina. Friction on the genitals can result in physical pleasure that can end in orgasm and ejaculation.
During ejaculation, semen exits the urethra (the opening at the tip of the penis) and enters the vagina. The sperm travels through the vagina and the uterus and then makes its way to the uterine tubes. Here it can fertilize an egg if it is available. The speed at which sperm cells travel varies a lot, so the time it will take for the egg to meet the sperm may be anywhere from about 30 minutes to a few days.
Because conception (when an egg is fertilized) is tied to ovulation (when an egg is released), this process of becoming pregnant occurs approximately two weeks before the next period starts. If the egg is not fertilized by sperm, it travels into the uterus and breaks up.
If sperm makes it into the uterine tube, once it has entered the egg, it changes in structure so that no other sperm can enter it. Within 24 hours, the fertilized egg starts dividing into a bundle of cells that develops into an embryo. The embryo then moves down the uterine tube towards the uterus, which it reaches approximately four days later.
The next stage of pregnancy is implantation. This is when the fertilized egg becomes attached to the wall of the uterus. Many people notice slight bleeding (or spotting) around the time of implantation.
About 10 days after fertilization, a hormone called human chorionic gonadotropin (hCG) is first produced. When hCG is high enough, it can be detected in blood or urine, usually by the time there’s a period delay. Pregnancy tests work by checking for the presence of hCG.
After implantation, the embryo continues to develop into a fetus. For the remainder of the pregnancy, the developing infant receives nutrition from the placenta — this is a temporary organ that also plays a role in controlling temperature and removing waste.
The brain, heart, and other important organs develop during the weeks and months that follow. A typical full-term delivery occurs after 39–40 weeks, but it is possible to give birth to perfectly healthy babies earlier than this.
So there you have it! Conception, pregnancy, and delivery from beginning to end!
Now that we’ve explained how pregnancy occurs, we’ll go over some common pregnancy misconceptions:
Ovulation is an important part of the process of becoming pregnant, whether from intercourse or other methods like IVF or IUI. Pregnancy happens when sperm fertilizes an egg that becomes implanted in the uterus. The fertilized egg grows into an embryo and develops into a baby over the following 40 weeks or so.
So strictly speaking, it’s not possible to get pregnant from intercourse if ovulation hasn’t occurred. But do bear in mind that sperm can survive for several days in the female reproductive system. This means it’s possible to have sex before ovulation and then become pregnant later, after ovulation has taken place.

Even before ejaculating semen, the penis releases a clear, colorless liquid that is called pre-ejaculate (or pre-cum). There’s still debate among scientists as to whether or not it contains sperm. Some research shows that some people produce precum that contains sperm, while others do not. Unless you’re trying to conceive, it’s better to assume pre-cum may contain sperm.
Knowing this is important if you’re using the withdrawal (also called pull-out) method to prevent pregnancy. The withdrawal method involves removing the penis from the vagina before ejaculation takes place. This is often unreliable for two reasons: It’s difficult to time an orgasm and ejaculation inside the vagina may mistakenly occur, and the possible low level of sperm in pre-ejaculate means that pregnancy can occur even if semen is not deposited in the vagina.
Pregnancy cannot happen directly because of anal sex. But the vaginal opening and the anus are extremely close to each other, so there is always the chance for sperm to flow into the vagina and travel to fertilize an egg. This is rather rare and unlikely, but still possible.
Oral sex is one type of sexual activity that won’t result in pregnancy. Stimulating someone’s genitals with the lips and tongue does not allow sperm anywhere near an egg, so no unexpected pregnancy will result from this activity.
The gastrointestinal tract and reproductive system are not connected, so if it’s swallowed, sperm cannot enter the vagina through this route.
Vaginal sex in any position carries a chance of pregnancy.
Fingering is when a partner stimulates the vagina with their fingers, and pregnancy from this is typically not possible. If the vagina is being penetrated by clean fingers without any semen on them, there’s no risk of becoming pregnant. If the fingers have traces of semen on them, coming into contact with the vagina can result in pregnancy.
Dry humping is also sometimes known as “outercourse.” This form of sexual activity cannot result in pregnancy because it does not allow semen into or around the vagina.
Semen cannot survive on a surface like a toilet seat or anything similar. This is because it depends upon a moist environment to survive. Pregnancy from making typical contact with a toilet is unlikely.
Orgasm is the intensely pleasurable climax to sexual intercourse. However, pregnancy can still result from intercourse that does not end in orgasm.
Because pre-ejaculate fluid from the penis may contain low levels of sperm, it’s still possible for pregnancy to occur without an orgasm. Also, there is not thought to be any relationship between the female orgasm and conception. Pregnancy can still occur even if neither partner has an orgasm.
Perimenopause describes the stage of a life when a person is approaching menopause. Although eggs are less plentiful and may be less healthy than in earlier stages of life, it’s still possible to become pregnant during this phase.
No. Washing or douching the vagina cannot prevent pregnancy. If semen is ejaculated into the vagina during sexual intercourse, it is buried deep in the reproductive system and cannot safely be removed by vaginal cleaning or douching.
And that’s that! You’ve walked through the whole process of conception and pregnancy with Flo, and along the way picked up all kinds of useful information about the most common misconceptions.