Any time a couple has sex and sperm enters the vagina, a pregnancy could happen. This is true no matter what position they have sex in, like standing up or having one person on top. Where doesn’t matter either. Someone can pregnant in a pool, hot tub, or any other place.

Why Can’t a Position Help Prevent Pregnancy?

Sperm can swim up against gravity, and they're fast. As soon as sperm are inside the vagina, they start racing toward the egg. When a couple has sex, sometimes it might seem like the ejaculate (“cum” or fluid that comes out of the penis during sexual excitement) leaves the vagina. But enough sperm can still get in to cause pregnancy.

Even "pulling out" out before reaching sexual excitement (orgasm) can still lead to a pregnancy. That's because some sperm may be in a male's pre-ejaculate (“pre-cum” or the bit of fluid that comes out of the penis at this time), and it can get into the vagina.

What Else Should I Know?

If you're having sex, use a reliable form of birth control, like an intrauterine device (IUD) or birth control pills, to protect against pregnancy. And couples also need to know about sexually transmitted diseases (STDs). STDs can spread through vaginal, anal, or oral sex; using fingers; or other sexual contact — no matter the position. Using a condom, finger condom, or dental dam each time you have sex can help prevent STDs.

The only way to fully prevent STDs and pregnancy is to not have sex.

If you have questions about sex, pregnancy, or STDs, talk with your doctor. Or you can go to a health clinic like Planned Parenthood.