The mucus plug is a thick clump of cervical mucus that forms during pregnancy, helping block the cervix. The cervix is the entrance from the vagina to the uterus.
When a person loses their mucus plug, it may mean that labor will begin soon. This start is usually within a few days or hours, but sometimes not for several more weeks. Some people call the loss of the mucus plug “bloody show.”
In this article, learn more about losing the mucus plug, including what it looks like and when to see a doctor.
The cervix is a doughnut-shaped muscle that acts as the “door” from the vagina to the uterus. During pregnancy, it closes tightly to keep the fetus in and prevent infections from entering the uterus.
The cervical mucus plug offers additional protection from anything entering the cervix and affecting the developing fetus.
Cervical mucus changes throughout a person’s reproductive life and menstrual cycle, largely due to hormonal factors. Shortly after conception, progesterone causes cervical mucus to become denser, thicker, and more acidic, forming the mucus plug.
The main symptom of the mucus plug falling out is the sudden appearance of blood tinged mucus. Some people experience labor symptoms, such as contractions, when this happens.
It is important not to confuse the loss of the mucus plug with other types of bleeding. While a small amount of bleeding is common in labor, excessive bleeding may warn of a hemorrhage, a placental abruption, or other complication.
Emerging research suggests that the role of the mucus plug is complex. The body’s ability to create a healthy mucus plug may even predict pregnancy outcomes.
The results of a 2013 study suggested that pregnant women at risk of giving birth prematurely were more likely to have issues with their cervical mucus. In these cases, their mucus did not form as strong a barrier, potentially offering less protection.
As the body prepares for labor, the cervix ‘ripens,’ which means that it gets softer, shorter, and begins opening. The cervix eventually opens enough for the mucus plug to fall out.
Sometimes, the plug falls out all at once. A person may notice a large glob of mucus and blood. The plug can also come out in pieces over time, so the individual might see a small and periodic trickle of mucus and blood, or perhaps not even notice the change at all.
While losing the mucus plug usually means that labor is coming soon, there is no way to predict exactly when it will happen.
Some people only lose their mucus plug after labor has begun. Others experience labor a few hours after the mucus plug falls out, while some wait days or even weeks.
Labor is different for every person, especially in the early stages when contractions tend to be irregular or weak.
Some signs that a person might go into labor soon include:
- changes in the shape, texture, or location of the cervix
- increase in cervical mucus
- changes in mood or behavior, such as a sudden burst of energy
- change in the position of the baby, or a pregnant belly that looks like it has “dropped”
Some early signs labor include:
- contractions that resemble menstrual cramps or abdominal pain
- a gush of fluid from the vagina
- low back pain
As labor progresses, contractions typically become more prolonged and more regular. They may also feel different.
False and early labor contractions tend to affect only the front of the body, and they may weaken with movement or if a person gets into water.
The real labor contractions typically begin in the back or at the top of the uterus and feel progressively stronger. They do not stop when a woman moves or takes a shower.
Losing the mucus plug is not usually harmful, but it may indicate a person is at risk of preterm labor if it happens before 37 weeks. People can speak to a doctor or midwife about any mucus-tinged blood that appears before full term.
People should go to the emergency room immediately if they:
- have sudden bleeding, especially with intense uterine pain
- develop a fever
- notice that the baby stops moving or moves less frequently
People can contact a doctor if:
- The pregnant woman experiences a gush of fluid from the vagina, typically a sign that the membranes have ruptured. The “water breaking” often means labor is imminent.
- The woman has other symptoms of labor.
- The woman is at risk of preterm labor, or a doctor has instructed to call immediately for signs of labor.
Anyone unsure whether they have lost their mucus plug should also call their doctor or midwife, and mention this at the next appointment.
Losing the mucus plug is a common symptom late in pregnancy. It usually means that labor will begin soon.
Though the mucus may look strange and the blood might be unsettling, the loss of the mucus plug is not a medical emergency unless a pregnant person has other symptoms, such as significant bleeding or signs of preterm labor.
The end of pregnancy and the beginning of labor can be confusing and uncertain times. A person might not know whether labor has begun, and they might worry that what appears to be a mucus plug is actually something else, such as abnormal bleeding.
Talk to a doctor or midwife during pregnancy about what signs warrant a visit or phone call. People may feel more secure to err on the side of caution and check with a healthcare professional about any new or unusual symptoms.