Can You Get Pregnant Right After Sex? Does Lying Down Help?

How quickly does conception happen and does remaining horizontal after sex help?

Woman relaxing on bed after sex
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You already know that sex leads to pregnancy. But how quickly does conception happen after intercourse? And can lying on your back help you get pregnant faster? Fertilization can occur within minutes of sex. However, it's also possible to have intercourse on Tuesday, but not conceive until Friday!

As for lying on your back after having sex in hopes of helping conception occur faster, it seems like it makes sense.

Sperm need to swim through the reproductive system. Perhaps it's easier for them to make the journey if they don't have to swim up—and can just swim horizontally. However, things are slightly more complicated than that.

Can You Get Pregnant Right After Sex?

Just how quickly do sperm swim and how soon after ejaculation can fertilization occur are two different questions.

Studies found that sperm take between 2 and 10 minutes to travel from the cervix through to the fallopian tubes (where they hope to meet an egg.) This is regardless of gravity. They will swim "up" through the uterus whether you're on your feet or standing on your head. If there is an egg waiting, conception can occur as quickly as three minutes after sexual intercourse.

However, sperm can survive inside the female reproductive system for up to five days. If you had sex on Monday, and you ovulate on Thursday, conception can occur days after you had sexual intercourse.

Sometimes, a doctor will estimate the day of conception based on how many weeks the fetus measures in an ultrasound, and this conception date doesn't match up with a day the couple had sex. This possible delay between intercourse and fertilization explains how that can happen. 

While you're more likely to get pregnant if you have sex two to three days before ovulation, you can get pregnant from sex that occurs up to six days before an egg is released from the ovary

Does Lying on Your Back After Sex Help You Get Pregnant Faster?

Just about every woman has received advice to remain on her back after sex, in hopes it'll make it easier to get pregnant. There’s no research specifically on lying still after sex to back up the claim.

However, there is research on the fertility treatment intrauterine insemination (or IUI). During IUI treatment, specially washed sperm are transferred directly to the woman’s uterus via the cervix through a thin catheter. In one study, researchers wanted to know if IUI treatment would be more effective if the woman remained on her back for 15 minutes after the procedure.

Researchers found that the women who remained on their backs for 15 minutes after the sperm transfer had a 27 percent pregnancy rate after three cycles. The women who were encouraged to get up right after the treatment had an 18 percent pregnancy rate after three cycles. Remaining horizontal did improve pregnancy rates. Whether that would translate to sexual intercourse, no one can say.

For How Long Should You Lie on Your Back?

If you’re going to lie on your back, how long should you stay there to reap any benefits?

Again, there’s no research on sexual intercourse to give us an answer.

However, we have another study on IUI that may give us a clue.

In this study, 396 couples having IUI treatment for male factor infertility, cervical issues, or unexplained infertility were randomly assigned to a post-IUI “rest” group. Women were either asked to remain horizontal for 5 minutes, 10 minutes, or 20 minutes post-insemination.

In this particular study, the clinical pregnancy rates were dramatically different between the 5 and 10-minute group. 

Clinical pregnancy rates per cycle:

  • 4.5 percent for those who remained horizontal for 5 minutes
  • 15.9 percent for those who remained horizontal for 10 minutes
  • 19.7 percent for those who remained horizontal for 20 minutes

The difference between the 10 and 20-minute groups was not considered to be statistically significant.

Therefore, the researchers suggest women remain lying down for at least 10 minutes after insemination.  

[Note: don't compare these results to the first study referenced above. This study looked at the pregnancy rate per cycle, while the first study mentioned in this article was looking at cumulative pregnancy rates after three treatment cycles.)

How Soon After Conception Will You Feel Pregnant?

Whether fertilization occurs within minutes of sex or days later, will you be able to feel you're pregnant when it happens? Unfortunately, no.

Some women claim to have "known" they conceived within minutes of sex. The truth is that it's scientifically impossible. Any potential pregnancy symptoms won't appear until embryo implantation (at the very, very earliest), and that doesn't happen for another 7 to 10 days. It takes time for the fertilized egg to travel from the fallopian tubes and find a soft landing area in the uterus.

Having pregnancy signs at the time of implantation is also unlikely. Most women don't start to experience pregnancy symptoms until they are a few days past their expected period. Some women never "feel" pregnant.

A Word From Verywell

With IUI, the sperm get a helpful push ahead into the uterus. But even with the push, lying down afterward seemed to boost pregnancy rates. Perhaps it is a good idea to lie still for about 10 minutes after sex.

That being said, don't stress over it. The research was on IUI, not sex. If you do want to try lying on your back, there's no reason to remain there longer than 15 minutes.

Also, standing up right after sex can't prevent pregnancy. Even if you had sexual intercourse and then jumped up and down right away, the sperm will swim up, and you can get pregnant.

If you need to use the bathroom right after sex (especially if you get frequent urinary tract infections), get up and go ahead. You’re not going to ruin your chances of conception.

Sources:

Custers IM, Flierman PA, Maas P, Cox T, Van Dessel TJ, Gerards MH, Mochtar MH, Janssen CA, van der Veen F, Mol BW. “Immobilisation versus immediate mobilisation after intrauterine insemination: randomised controlled trial.” British Medical Journal. 2009 Oct 29; 339:b4080. doi: 10.1136/bmj.b4080

Oriefa, Yasser Ibrahim; El-agwanya, Ahmed Samy; Darwisha, Emad Abd Elmoneem; b, Noha Mustafa Salima. “The effect of bed rest after intrauterine insemination on pregnancy outcome.Middle East Fertility Society Journal. Volume 20, Issue 1, March 2015, Pages 11–15.       

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