When Does Labor Start After Losing Your Mucus Plug?

When you are pregnant, your body produces a thick mucus to block (or plug) the cervix, the opening to the uterus from the vagina. This mucus protects the uterine environment from infection and repels bacteria from the outside, says Kristin Mallom, CNM, board-certified nurse midwife and chief strategy officer at Integrative Obstetrics in Jersey City, New Jersey.

Toward the end of pregnancy, small uterine contractions can start to open up the cervix, says Adeeti Gupta, MD, an OB-GYN and the founder of Walk In GYN Care. The cervix will also begin to soften due to hormonal changes, leading it to open up further and eventually release the mucus plug in the process.

Some people will notice the loss of their mucus plug the moment it happens (it looks like a gelatinous blob of snot). It can be yellowish-white and tinged with red, pink, or brown streaks. Or you may not notice it at all. If you do see it, labor is on its way. But how long after losing your mucus plug does labor usually start? Here's what the experts say.

Does Losing the Mucus Plug Mean I'm Going Into Labor?

According to the American College of Obstetricians and Gynecologists (ACOG), the mucus plug comes out through the vagina as the cervix begins to dilate in preparation for labor. So, yes, losing your mucus plug does signal labor, but not right that second.

"The loss of the mucus plug, especially when there's a little bit of blood, is usually a good indicator that labor is coming within one to three days," explains Mallon. "But sometimes labor will come weeks after losing the mucus plug, so this guideline isn't 100% accurate." In other words, losing your mucus plug signals that labor is approaching, but it may still take a while.

Don't worry: Your baby is still protected after the mucus plug falls out. "Your cervix continues to produce mucus to replenish what is lost, and the amniotic fluid has many immunological agents that continue to protect baby against infection," says Clara Ward, MD, a maternal-fetal medicine specialist in Houston.

What Should I Do After Losing My Mucus Plug?

If you are aware that you've lost your mucus plug, you may be tempted to grab your hospital bag and run out the door. Instead, be on the lookout for other signs of labor, including:

• Contractions that get progressively longer, stronger, and closer together
• Contractions that continue even when you move around
• Contraction pain that starts in the back and moves to the front
• Lightening (the baby drops into your pelvis)
• Your bag of water ruptures (aka your water breaks)

If you notice signs of labor, give your health care provider a call. If it's after hours and you've lost your mucus plug, you can report it to them the next day—or even at your next appointment, says Mallon. For now, it's better to monitor your baby's movements.

"If contractions start, time them," says Dr. Gupta. "When they become regular—lasting at least 30 seconds and coming every three to five minutes—then you can go to the hospital. You should also head to the hospital if your amniotic sac ruptures (commonly known as your "water breaking").

There is an exception to these rules: Call your health care provider's office for recommendations if you lose their mucus plug before your 37th week of pregnancy. Losing your mucus plug before week 37 isn't necessarily cause for concern, especially if this isn't your first pregnancy, but you should still have your provider advise on possible complications like preterm labor.

Keep Watch for Other Signs of Labor

After you lose your mucus plug, be on the lookout for additional indications that you are in labor. "Other signs include 'lightening,' or the sensation that the baby has 'dropped,'" says Dr. Ward. "While this may result in more pressure in the pelvic region, breathing may be easier."

Some people feel more cramping or back pain as their labor contractions start. You may feel less active and more fatigued, or experience a feeling of loose joints.

Your health care provider can determine whether your cervix has started to dilate, and there may actually be telling lines on your buttocks. Known as the "purple line," this discoloration begins at the anus and extends up the butt crack at the onset of active labor. Research has found that it appears in about 75% of pregnant people during labor, making it a non-invasive method for assessing labor progression.

Then, stay calm. "If you are full-term—more than 37 weeks—there is probably no need to call your doctor unless you are bleeding heavily, contracting regularly, the mucus is particularly foul-smelling, or you are concerned that you may have broken your water," says Dr. Ward. In addition, keep an eye out for a fever or green or yellow amniotic fluid discharge.

Still worried? Call your health care provider just to be safe.