The mucus plug is a protective seal that forms within the cervix early in pregnancy. Its primary role is to block the opening of the uterus, creating a barrier to help prevent bacteria and other potential sources of infection from reaching the developing fetus. This thick collection of mucus is a normal and temporary feature of pregnancy.
Visual Characteristics
The appearance of the mucus plug can vary considerably, but it is generally described as a thick, jelly-like, or stringy substance. Its color can range from clear, off-white, yellowish, brownish, or blood-tinged. This blood-tinged appearance is often due to small blood vessels in the cervix rupturing as it begins to soften and dilate in preparation for labor.
The texture is typically more substantial and sticky than regular vaginal discharge, which is usually thinner and lighter in color. When expelled, the mucus plug might appear as a single glob. However, it can also come out gradually in smaller pieces over time, making it less noticeable for some individuals.
When It Passes and What It Means
The passing of the mucus plug typically occurs in late pregnancy, often after 37 weeks, as the cervix begins to dilate and efface in preparation for labor. While it signals the body is preparing for birth, its expulsion does not always mean labor is immediate; labor could begin within hours, days, or even weeks.
The body continuously produces new mucus, so even if the plug is expelled, the cervix continues to secrete fresh mucus, maintaining a protective barrier. It is also important to distinguish the mucus plug from “bloody show.” While the mucus plug can be blood-tinged, “bloody show” specifically refers to a discharge of mucus mixed with blood that results from the cervical changes. The terms are sometimes used interchangeably, but “bloody show” specifically emphasizes the presence of blood.
When to Contact a Healthcare Provider
There are specific situations that warrant contacting a healthcare provider. If the mucus plug is expelled before 37 weeks of pregnancy, seek medical advice as it could be a sign of preterm labor or other complications.
Individuals should also contact their doctor or midwife immediately if they experience significant, bright red bleeding that is more than just streaks or a small amount, especially if accompanied by pain or contractions. A sudden gush of clear fluid from the vagina, which could indicate the membranes have ruptured (water breaking), also requires immediate medical attention. Any concerns about unusual discharge color (e.g., green or foul-smelling), fever, or a significant decrease in fetal movement should prompt a call to a healthcare provider.