Green discharge during pregnancy is not normal and almost always signals an infection that needs treatment. The most common causes are sexually transmitted infections like trichomoniasis, chlamydia, and gonorrhea. While these infections are treatable during pregnancy, leaving them unaddressed can lead to serious complications including preterm birth and low birth weight, so prompt testing matters.
What Causes Green Discharge
Normal pregnancy discharge (called leukorrhea) is thin, white or milky, and mild-smelling. When discharge turns green or yellow-green, it typically means your body is responding to a bacterial or parasitic infection. The three infections most commonly behind green discharge are trichomoniasis, chlamydia, and gonorrhea.
These infections share overlapping symptoms, which makes it impossible to tell them apart by appearance alone. All three can produce green or yellow-green discharge, an unpleasant vaginal odor, burning or itching, and discomfort when urinating. A lab test, usually a vaginal swab, is the only reliable way to identify which one you’re dealing with.
Trichomoniasis
Trichomoniasis (often called “trich”) is caused by a parasite and is one of the most common STIs in the United States, affecting an estimated 3.7 million people. It produces a thin discharge that can range from white to yellowish to greenish, often with a fishy smell. You may also notice genital redness, itching, burning during urination, or discomfort during sex.
In pregnancy, trichomoniasis carries specific risks. Pregnant people with trich are more likely to deliver early, and their babies are more likely to have a low birth weight (under 5.5 pounds). The good news is that treatment is safe at any stage of pregnancy. Oral antibiotics are the standard approach, and multiple studies have found no evidence of harm to the developing baby from the medication used.
Chlamydia and Gonorrhea
Chlamydia is the most frequently reported bacterial STI in the United States. It can cause green discharge, a bad smell, burning, itching, and bleeding after sex. Some people have no symptoms at all, which is why routine screening during pregnancy is standard practice.
Gonorrhea produces nearly identical symptoms: green discharge, odor, burning, and urinary discomfort. It’s most common in younger adults. Both infections are treated with antibiotics that are safe to use in pregnancy. Left untreated, either one can spread to the uterus and increase the risk of complications during delivery, including passing the infection to the baby.
Bacterial Vaginosis
Bacterial vaginosis (BV) is technically an imbalance of vaginal bacteria rather than a single infection. Its hallmark is a thin, off-white or grayish discharge with a fishy odor, but it can sometimes appear yellowish-green. BV is common in pregnancy, and its effects on birth outcomes are significant.
Research published in Frontiers in Surgery found that women with BV had a preterm birth rate (before 34 weeks) nearly four times higher than women without it: 22.7% versus 6.2%. Babies born to mothers with BV were also more likely to need intensive care after birth. Over half of the women with BV in the study showed signs of infection spreading to the membranes surrounding the baby. These elevated risks persisted even when treatment was given, which underscores why early detection makes a difference.
Green Fluid vs. Green Discharge
If you’re past 37 weeks, there’s another possibility to consider. A sudden gush or steady trickle of greenish-brown fluid could be amniotic fluid stained with meconium, your baby’s first stool. This happens in 12% to 20% of all births and is most common at full term (40 weeks) or past the due date.
Meconium-stained fluid looks and feels different from vaginal discharge. It comes out more like water than mucus, and it’s typically greenish-brown rather than bright green. If you see this, it means your water has broken and your baby has passed stool in the womb. This situation needs immediate medical attention because there’s a risk the baby could inhale the meconium during delivery.
Symptoms That Need Urgent Attention
Green discharge on its own warrants a call to your provider, but certain combinations of symptoms are more urgent. Contact your care team right away or go to the emergency room if your green discharge is accompanied by:
- Fever, especially combined with severe belly or back pain, trouble urinating, or foul-smelling discharge
- Fluid leaking that is bloody or greenish, which may indicate your membranes have ruptured
- Severe belly pain that doesn’t go away, starts suddenly, or gets worse over time
- Dizziness or light-headedness alongside vaginal fluid leaking
Any vaginal bleeding or fluid leaking during pregnancy is considered an urgent warning sign on its own. If you can’t reach your provider, an emergency room visit is appropriate.
What Testing and Treatment Look Like
Your provider will likely do a vaginal swab to test for the infections described above. Results can come back within a day or two for most tests, though some rapid tests give same-day answers. You may also be tested for other STIs at the same time, since co-infections are common.
Treatment for all of these infections during pregnancy involves oral antibiotics. For trichomoniasis specifically, the standard antibiotic has been studied extensively in pregnant women and shows a low risk to the fetus, with no evidence of birth defects or genetic effects. Treatment is recommended regardless of which trimester you’re in. Your sexual partner will also need treatment to prevent reinfection, and you’ll typically need to avoid sex until both of you have completed the course.
After treatment, your provider may retest you later in pregnancy to confirm the infection has cleared. This is especially important because reinfection is common, and the risks to your pregnancy remain as long as the infection is active.