Planned Parenthood

How Pregnancy Happens

How Pregnancy Happens

How pregnancy happens at a glance:


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How do you get pregnant?





  • kissing
  • masturbation
  • body rubbing
  • oral sex
  • anal sex


How can I avoid pregnancy?

There are two ways to avoid pregnancy:

  • Don't have sex.







Can I get pregnant only at certain times of the month?

There are certain times of the month when it’s more likely that you’ll get pregnant from having sex.  But, it’s possible to get pregnant anytime you have unprotected vaginal (penis-in-vagina) sex.

Even if you’re on your period, about to get your period, or just had your period, it’s possible to get pregnant from unprotected sex. It’s even possible to get pregnant before you have your first period. And the number of times you’ve had sex doesn’t matter either: whether it’s your first time having sex or the 100th time, you could get pregnant.

So having vaginal sex — at any time — means you need to make choices about birth control and preventing STDs.

How long does it take to get pregnant after sex?

Pregnancy doesn't start the moment a penis ejaculates in a vagina. It can take up to six whole days for the sperm and egg to join and form a fertilized egg. During these six days, sperm are hanging out in the reproductive organs, waiting for an egg to show up.

But since sperm swims through the vagina up to organs deep in your body, you can’t avoid pregnancy by trying to wash out the sperm. Once they’re in there, there’s no catching them.

Then, it takes another six to ten days for the fertilized egg to attach itself to the lining of the uterus. Pregnancy begins once all this happens.

If you’re concerned about unintended pregnancy after having unprotected vaginal sex, you may want to consider emergency contraception (EC), also known as the morning-after pill. EC prevents pregnancy AFTER unprotected sex.  EC is not the same thing as the abortion pill, and it will not work if you’re already pregnant.

EC only works if you take it within 120 hours (5 days) after unprotected sex. And the sooner you take it, the better.

Should I take the morning-after pill (emergency contraception)?

If you had vaginal sex in the last five days and did not use a condom or birth control or if the condom broke or slipped off, you should use emergency contraception if you do not want to get pregnant. It prevents pregnancy after unprotected sex, but it does not end a pregnancy (cause an abortion).

It is effective if started within 120 hours (5 days) after unprotected sex. The sooner you take it, the better it works.

Plan B One-Step is a brand that’s available in the family planning aisle (where the condoms are) of many drugstores. Anyone can buy it, no matter how old you are. Other brands of EC, like Next Choice One Step, are available without prescription at many pharmacies for anyone 17 or over. Teens under 17 can still get these other brands of EC with a prescription.

Remember, the sooner you take EC, the better it works. For more information on emergency contraception, contact your local Planned Parenthood health center.


How do I know if I’m pregnant?

Missing your period after having unprotected sex is the biggest sign that you might be pregnant. If your period is late, take a pregnancy test.

But there are a lot of things besides pregnancy that can cause a late or missed period, including stress, illness, not eating enough, too much exercise, or using a birth control method that contains hormones. Having a period that comes later than usual or missing a period is pretty common in teens, because it can take a few years for your cycle to become regular.

So the only way to know for sure if you're pregnant is to take a pregnancy test. You can get a pregnancy test at a drugstore or health center. At-home pregnancy tests are 99 percent accurate when taken after a missed period.

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How Pregnancy Happens