How Long After Sex Does Labor Start?

As soon as you hit term, your body is firing off hormone fireworks in preparation for labor. These chemicals release prostaglandins, which help the cervix soften and prepare for birth. Sexual activity also releases oxytocin, which helps induce contractions—that’s why doctors use synthetic oxytocin when inducing labor at the hospital.

Sex After Water Break

As your due date approaches, you may be feeling more and more ready to put pregnancy behind you. And you may be hoping that the baby will start kicking sooner rather than later. But before you go reaching for the sex to induce labor, consult with your doctor or midwife and follow their recommendations for your specific situation.

If you’re already in the final stretch of your pregnancy, it’s unlikely that sex can bring on labor. The hormones released during sexual activity—including oxytocin and prostaglandins—will likely help, but they’re not enough to kick things off on their own. Your doctor will probably want to see you again within 24 hours of your water breaking and make sure that everything is progressing as it should.

That’s because your body may have to re-balance the chemicals that it releases in response to sexual activity in order to start labor. Oxytocin dilates blood vessels and encourages your uterus to contract, while protaglandins soften the cervix. Both of these hormones are produced during sexual intercourse, and semen has the highest concentration of them. In fact, synthetic versions of oxytocin are used to induce labor at the hospital when medically necessary.

Sex will likely also release a lot of nitric oxide, which helps to open up the arteries and veins in your pelvic area and make them more flexible. Nitric oxide can also help to prevent clots, so it’s an important part of your body’s natural process for bringing on contractions. It’s the same mechanism that makes long walks or spicy foods less effective ways to trigger labor.

But there’s one time when you definitely shouldn’t get it on: after your water breaks. Having sex after your water breaks can increase the risk of infection, which could harm both you and your baby. Every time a foreign object enters the vagina, you’re at increased risk for infection, and this is no different.

While it’s true that sex can trigger uterine contractions, the most common cause of those contractions is your body’s own hormone fireworks—like those created during sexual intercourse. If you’re still hoping to speed things up, you can try to encourage them with nipple stimulation and long walks, but be sure to talk to your doctor before trying anything at home.

Sex Before Water Break

If you’re at full term, you’ll probably start to feel contractions (called Braxton Hicks) regularly by now. You may even think they’re a sign that you’ve gone into labor. But, sadly, sex won’t turn those twinges into real labor, despite what you may have heard from friends or family. That’s because the only thing that can really bring on your baby’s arrival is a natural cause like a bloody show or ruptured membranes.

Sex and sexual activity, including foreplay such as touching the nipples or breasts, does release oxytocin, which causes contractions in the uterus. However, this effect may be less powerful than the synthetic oxytocin that’s used to induce labor in the hospital. The oxytocin released during sex also helps the cervix ripen to prepare for birth. It may even trigger labor by itself if the cervix is already ripe enough.

In addition to releasing oxytocin, sex also increases secretion of prostaglandins, which are chemical compounds that have hormone-like effects. Prostaglandins help ripen the cervix, and they can also make it more sensitive and prone to uterine contractions. Semen contains the most concentrated form of prostaglandins, so it’s no wonder that some women believe sex can speed up the start of labor.

The problem is that no high-quality studies have been done to verify whether sex can actually induce labor. The best way to test this would be a randomized controlled trial in which one group of pregnant women has sex and another group doesn’t. Unfortunately, this type of study is difficult to do at the end of a pregnancy when many women are so eager for their baby to arrive.

There are plenty of other methods you’ve probably heard about that claim to be able to trigger labor, such as eating spicy foods. While these can certainly make you sweat and increase your heart rate, they don’t actually work to stimulate a woman’s contractions or bring on labor. If you are interested in trying other methods to trigger labor, talk to your doctor for a recommendation. Also, never have sex after your water breaks, as this could lead to infection that could harm both you and your baby. If you have a low-lying placenta or have experienced leaking vaginal fluid, it’s especially important to avoid having sex. If your waters break, call your doctor or go to the emergency room right away for evaluation and treatment of the infection.