Vaginal discharge is produced continuously by cells lining the uterus, cervix, and vagina. These epithelial cells secrete fluid that lubricates the vaginal canal, flushes out dead cells, and actively fights off harmful bacteria. On average, the body produces less than one teaspoon of discharge per day, though the amount shifts throughout the menstrual cycle, during pregnancy, and after menopause.
Where Discharge Comes From
Discharge isn’t made by a single gland. It’s a combined product of fluid from several sources. The epithelial cells that line the cervix and vaginal walls constantly release a mucus-based fluid. This fluid contains water, proteins, and a mix of immune molecules, including natural antibiotics called defensins and a protein called lactoferrin that fights bacteria and reduces inflammation. Together, these components form the bulk of what you see as daily discharge.
A separate set of glands, the Bartholin glands, sit near the vaginal opening and produce a different type of fluid specifically during sexual arousal. That lubrication is triggered by nerve signals from the pudendal nerve, which provides both sensory and involuntary stimulation to those glands. This arousal fluid serves a distinct purpose from the discharge your body makes around the clock.
How Bacteria Keep Discharge Healthy
Healthy discharge is not sterile. It contains large numbers of Lactobacillus bacteria, which play a central role in vaginal health. These bacteria break down glycogen (a sugar stored in vaginal cells) and convert it into lactic acid. That lactic acid drops the vaginal pH to between 3.8 and 4.5, making the environment too acidic for most harmful organisms to survive.
The protective effects go beyond acidity. Lactobacilli also produce hydrogen peroxide, which kills oxygen-sensitive bacteria, along with other antimicrobial compounds that block pathogens from physically attaching to the vaginal walls. One species in particular, L. crispatus, produces the most protective form of lactic acid and is associated with the strongest defense against urogenital infections. When L. crispatus dominates, the vaginal environment also becomes less inflammatory, meaning less irritation and fewer symptoms overall.
Research on vaginal fluid shows it selectively kills nonresident bacteria like E. coli and Group B Streptococcus while allowing protective Lactobacillus species to thrive. The antimicrobial activity comes from a combination of low pH, high lactic acid content, and antimicrobial proteins in the fluid itself.
How Discharge Changes Throughout Your Cycle
Hormones are the main driver of how discharge looks and feels from day to day. Estrogen and progesterone shift in predictable patterns across the menstrual cycle, and discharge follows those shifts closely.
- Days 1 to 4 (after your period ends): Discharge is dry or tacky, usually white or slightly yellow.
- Days 4 to 6: Slightly damp and sticky, still white.
- Days 7 to 9: Creamy, with a yogurt-like consistency. Wet and cloudy.
- Days 10 to 14 (around ovulation): Stretchy and slippery, resembling raw egg whites. This is the wettest point in the cycle. The texture makes it easier for sperm to travel through the cervix.
- Days 15 to 28 (after ovulation): Thick and dry again, remaining that way until menstruation starts.
These changes happen because estrogen peaks just before ovulation, thinning the cervical mucus and increasing its volume. After ovulation, progesterone takes over and thickens the mucus back up. Tracking these patterns is one of the methods some people use to identify their fertile window.
Discharge During Pregnancy
Pregnancy typically brings a noticeable increase in discharge, often called leukorrhea. This happens because of rising estrogen levels and increased blood flow to the pelvis. The extra discharge serves a practical purpose: it helps maintain the balance of protective bacteria and clears away dead cells more efficiently during a time when the body is especially vulnerable to infection.
Pregnancy discharge is usually thin, white or milky, and mild-smelling. Changes in color, texture, or odor during pregnancy can signal an infection and are worth paying attention to.
What Changes After Menopause
As estrogen declines during menopause, the volume of vaginal fluid drops and the acid balance shifts. The pH rises above 4.5, which means the protective acidity weakens. The vaginal walls also become thinner and less elastic, a condition sometimes called vaginal atrophy or genitourinary syndrome of menopause. Discharge may become scant, and some people notice an unusual yellowish color. These changes can also increase susceptibility to infections that the acidic environment previously kept in check.
When Discharge Signals a Problem
Normal discharge ranges from clear to white, with a mild or no odor. Several specific changes point to common infections:
- Dark gray discharge with a foul or fishy smell is a hallmark of bacterial vaginosis, which occurs when Lactobacillus populations drop and other bacteria overgrow.
- Thick, clumpy discharge resembling cottage cheese, especially with itching or a pink or green-yellow tint, often indicates a yeast infection.
- Frothy, greenish-yellow discharge with a strong odor can be a sign of trichomoniasis, a sexually transmitted infection.
Color alone doesn’t always tell the full story. A combination of unusual color, a change in texture, a strong odor, and symptoms like itching or burning together give a more reliable picture than any single sign on its own. Discharge that changes suddenly or dramatically from your personal baseline is the most useful signal that something has shifted.