Green vaginal discharge during pregnancy is typically a sign of infection. Normal pregnancy discharge, called leukorrhea, is thin, milky white, and mild-smelling. When discharge turns green, yellow-green, or has a strong odor, something beyond normal hormonal changes is likely going on. The most common culprits are sexually transmitted infections like trichomoniasis, chlamydia, or gonorrhea, though bacterial vaginosis can also produce greenish discharge.
What Normal Pregnancy Discharge Looks Like
Your body produces more vaginal discharge throughout pregnancy, starting in the first few weeks. This is completely normal. The discharge is your body’s way of maintaining the vagina’s pH balance and keeping harmful bacteria out. It’s usually white or milky white, thin in consistency, and either odorless or very mild-smelling.
As pregnancy progresses, this discharge often becomes heavier, thicker, or more opaque. None of that is cause for concern on its own. The shift from normal to abnormal happens when discharge changes color to green, bright yellow, or grey, develops a strong or fishy smell, or comes with itching, burning, or pain.
Trichomoniasis Is the Most Common Cause
Trichomoniasis, a sexually transmitted infection caused by a parasite, is one of the most frequent reasons for green discharge during pregnancy. The discharge is often described as thin, frothy, and greenish with a fishy smell. Other symptoms can include genital redness, burning or itching, discomfort when urinating, and pain during sex. Some people with trichomoniasis have no symptoms at all, which means the infection may have been present before pregnancy began.
Risk factors include having multiple sexual partners, a previous trichomoniasis infection, a history of other STIs, or not using condoms. About 20 percent of people treated for trichomoniasis contract it again within three months, so both partners typically need treatment.
Left untreated during pregnancy, trichomoniasis raises the risk of preterm birth and delivering a baby with low birth weight (under 5.5 pounds). A large review of over 81,000 pregnancies found that trichomoniasis was linked to a 42 percent higher risk of preterm delivery and a 51 percent higher risk of the baby being small for gestational age. The infection can also be passed to the baby during delivery.
Bacterial Vaginosis and Other Infections
Bacterial vaginosis (BV) happens when the normal balance of bacteria in the vagina gets disrupted. It can produce discharge ranging from dirty white to yellowish green, often with a fishy odor. BV is extremely common during pregnancy, affecting 15 to 42 percent of pregnant people. It doubles to quadruples the risk of preterm birth and premature rupture of membranes if untreated.
Chlamydia and gonorrhea can also cause greenish or yellowish discharge during pregnancy. Both are bacterial STIs that may produce few or no obvious symptoms beyond the discharge itself, which makes testing especially important. These infections carry their own risks for pregnancy complications and can be transmitted to the baby during birth.
How Your Provider Will Diagnose It
Diagnosing the cause of green discharge is straightforward and painless. Your provider will collect a small sample of vaginal discharge, usually with a swab, during a pelvic exam. From there, several tests can narrow down the cause.
For trichomoniasis, the sample can be examined under a microscope or tested with rapid antigen or DNA-based tests that return results quickly. For bacterial vaginosis, your provider may check the sample’s pH (BV pushes vaginal pH above 4.5), test for a fishy odor when a chemical solution is added, or look for specific “clue cells” under a microscope. These cells have fuzzy borders that indicate bacterial overgrowth. Chlamydia and gonorrhea are diagnosed through similar swab-based tests.
Treatment During Pregnancy
The standard treatment for trichomoniasis and bacterial vaginosis during pregnancy is an antibiotic called metronidazole. Research involving over 5,000 pregnancies found no increased risk of birth defects from metronidazole use. A separate study of more than 4,000 pregnancies with early exposure found no higher chance of miscarriage. The medication is also not expected to increase the risk of preterm delivery or low birth weight.
Chlamydia and gonorrhea are treated with different antibiotics that are also considered safe during pregnancy. Your provider will choose the right medication based on which infection is confirmed. Treatment is important not just for relieving symptoms but for reducing the risk of preterm birth and protecting the baby from infection during delivery.
Comfort Measures While You Wait for Treatment
If you’re dealing with itching or burning alongside green discharge, a few simple steps can ease discomfort before or during treatment. Soaking in a lukewarm (not hot) bath with four to five tablespoons of baking soda for 10 minutes can help with itching and burning. You can also pour lukewarm water over the vulva while urinating to reduce stinging.
Wear loose-fitting, white, all-cotton underwear during the day and skip underwear at night to let air circulate. Avoid scented products entirely: no hygiene sprays, perfumed soaps, scented pads, or baby wipes near the vaginal area. Switch to unscented white toilet paper and cut back on laundry detergent, using about a third of the recommended amount and running an extra rinse cycle. Skip fabric softeners and dryer sheets, as residual chemicals in underwear can worsen irritation.
Late Pregnancy: When Green Fluid Means Something Different
In the third trimester, a sudden gush or steady trickle of greenish fluid could be something other than vaginal discharge. Amniotic fluid that appears green or brown-green may be stained with meconium, the baby’s first stool. This occurs in 5 to 20 percent of labors and becomes more common as pregnancy goes past the due date, reaching about 27 percent at 42 weeks.
Meconium-stained fluid looks and behaves differently from infectious discharge. It tends to come out in a larger volume, resembles watery fluid rather than mucus, and usually appears during labor or after the water breaks. If you notice a gush of greenish fluid at any point in the third trimester, especially if it soaks through clothing, contact your provider or go to labor and delivery right away. Meconium in the amniotic fluid is associated with risks to the baby including breathing problems and infection, and your medical team will want to monitor the situation closely.