Glands located in the cervix and entrance of your vagina secrete mucus that lubricates and protects the vaginal tissue. This mucus mixes with other fluids to yield normal vaginal secretions. Normal vaginal fluid is slightly acidic and consists mostly of water, mucus and other proteins. The characteristics of cervical and vaginal mucus and vaginal discharge change in response to many factors, including your age, menstrual status and medical conditions.
Hormone levels vary throughout the menstrual cycle, causing changes in the amount, consistency and composition of your vaginal discharge. During the first half of your cycle, the amount of cervical mucus production gradually increases. Production peaks around the time of ovulation, when the vaginal discharge is typically clear, somewhat watery and slippery -- resembling the consistency of egg whites. If pregnancy doesn't occur, your cervical mucus typically becomes progressively thicker, more whitish and less abundant. This occurs primarily due to falling estrogen and increasing progesterone in your bloodstream.
Influence of Hormonal Contraception
Hormonal birth control -- in the form of pills, vaginal rings, patches or depot shots -- alters the amount and consistency of mucus in your vaginal discharge. This form of contraception co-opts your body's usual menstrual hormone production by supplying an external source of female hormones. The effect of hormonal contraception on the amount and consistency of your mucus depends primarily on the dosage of estrogen and synthetic progesterone -- progestin -- in your chosen method. In general, however, the progestin in hormonal birth control causes thicker cervical mucus. This is particularly notable in women using progestin-only methods, such as the mini-pill or depot shots. Thicker cervical mucus helps prevent pregnancy by preventing sperm from reaching your uterus and ovarian tubes.
Increased vaginal discharge normally occurs during pregnancy. This discharge, or leukorrhea, begins in the first trimester and continues throughout your pregnancy. This occurs, in part, because increasing blood estrogen levels stimulate the cervical glands to produce more mucus. As your delivery date approaches, you'll likely notice some thick mucus in your vaginal discharge. This occurs as a ball of cervical mucus -- known as the cervical plug or "show" -- is displaced in preparation for labor and delivery.
Several medical conditions can affect the amount, color and consistency of your vaginal discharge with variable amounts of mucus. Increased discharge often occurs when an imbalance in the normal vaginal bacteria occurs, leading to overgrowth of certain types. This condition, known as bacterial vaginosis, can cause a thin grayish discharge with an unpleasant fishy odor. Infection or overgrowth of yeast can cause thick, copious, curd-like, white vaginal discharge. Sexually transmitted infections are another consideration if you experience increased vaginal discharge. Possibilities include:
-- trichomoniasis, commonly known as "trich"
-- pelvic inflammatory disease, or PID
Polyps or cancer of the cervix or uterus are considerations if other more common causes of unusual vaginal discharge have been ruled out. A forgotten tampon can also cause vaginal irritation and unusual discharge.
Talk with your healthcare provider if you experience an unexplained change in your vaginal discharge, especially if it is accompanied by symptoms such as:
-- vaginal or genital burning, pain or itchiness
-- a foul smell
-- abdominal or pelvic pain
-- painful intercourse
Reviewed by: Tina M. St. John, M.D.