The mucus plug is a protective seal that forms early in pregnancy, blocking the opening of the cervix. This thick barrier, composed of cervical secretions, functions to shield the uterus and the developing fetus from bacteria and other infectious agents that may travel up from the vagina. Its eventual expulsion is a normal and expected sign that the body is preparing for childbirth, typically occurring in the late stages of pregnancy.
Normal Appearance and Odor
A healthy, normal mucus plug is characterized by a consistency that is thick, sticky, and gelatinous, often described as similar to raw egg whites or a clump of jelly. When intact, it can measure about one to two inches in length and may amount to one to two tablespoons in volume, though it can also be released gradually in smaller pieces over time. Its color is generally clear, off-white, or yellowish-white.
A normal mucus plug is essentially odorless, or it may have only a very mild scent. The mucus plug may also be tinged with pink, brown, or red streaks of blood, which is commonly known as the “bloody show.” This light bleeding occurs because tiny capillaries in the cervix can rupture as it begins to soften and dilate.
When the Smell Signals a Problem
A noticeable, strong, or unpleasant odor from the discharged mucus is a potential sign that an infection may be present. While the normal mucus plug is odorless, a foul smell should prompt a call to a healthcare provider for evaluation. Specific concerning smells include a fishy or generally foul odor, which can be symptomatic of conditions like bacterial vaginosis (BV).
The color of the mucus can also provide clues about underlying issues, especially when combined with a strong odor. If the mucus is green or gray, this may indicate a vaginal infection that requires medical attention. Other accompanying symptoms like itching, soreness, or pain during urination also suggest a possible infection alongside the change in discharge.
What to Do After the Mucus Plug Passes
The passage of the mucus plug signals that the cervix is beginning to soften and prepare for labor, but it does not mean that delivery is imminent. It is common for the mucus plug to be lost anywhere from a few hours to a few weeks before labor actually begins. Since this is a normal part of late pregnancy, if you are full-term, which is 37 weeks or more, and there are no concerning symptoms, you can generally mention it to your healthcare provider at your next appointment.
Contact your doctor immediately if the discharge is accompanied by heavy, bright-red bleeding, which may signal a complication like placental abruption or placenta previa. Seek immediate medical advice if you experience a sudden gush or continuous trickle of clear, watery fluid, suggesting your water has broken. If the mucus plug passes before 37 weeks of pregnancy, or if you notice any of the concerning colors or foul odors, contact your provider right away.