Yellow Discharge During Pregnancy: 7 Common Causes

August 2022

Yellow discharge during pregnancy can be a sign of infections, like a yeast infection, bacterial vaginosis, trichomoniasis or chlamydia. It can also occur with elimination of the mucus plug, or with leaking amniotic fluid. 

This type of discharge can emerge with other symptoms, like a foul odor, genital itching or pain or burning with urination. You should follow up with your obstetrician if you notice these symptoms to avoid complications in your pregnancy. 

If you have yellow discharge during pregnancy, you are advised to see your obstetrician to identify a cause an inidicate appropriate treatment. Treatment will vary based on the underlying cause. 

The most common causes of yellow discharge during pregnancy are:

1. Yeast infection

A yeast infection is a vaginal infection caused by Candida albicans fungus. This fungus is naturally found in the vagina, but excess amounts can cause a white, cottage cheese-like discharge which can also be yellow tinged. A yeast infection can also cause symptoms like intense genital itching, redness, vulva swelling and burning with urination. 

This type of infection is very common during pregnancy, as the normal hormonal changes that occur can cause imbalances in the vaginal flora, leading to fungal growth. Learn more about what causes a yeast infection and symptoms that can happen. 

Although it does not affect the baby’s development in-utero, a yeast infection should be treated prior to delivery, so that the baby does not catch an oral fungal infection (also known as thrush). 

What to do: You should see a doctor to start treatment, which can involve the use of topical or oral antifungals. 

2. Bacterial vaginosis

Bacterial vaginosis is an infection caused by the overgrowth of bacteria that are naturally found in the vagina (mostly Gardnerella sp. bacteria). It causes intense itching, burning or discomfort when urinating, a foul fishy smell which worsens with sex, and a thin yellow discharge that could also be white or gray in color. Read about other symptoms of bacterial vaginosis and what can cause this infection. 

If BV is left untreated in pregnancy, it can increase the risk for spontaneous miscarriage, premature labor, membrane rupture, endometritis, chorioamnionitis and low birth weight. It is also associated with a higher risk of STI transmission. 

What to do: You should see your obstetrician to confirm a diagnosis and start treatment as necessary, which can involve the use of antibiotics that are safe for pregnancy, like metronidazole or clindamycin. 

3. Chlamydia

Chlamydia is a sexually transmitted infection caused by Chlamydia trachomatis bacteria. It causes symptoms like yellow pus-like discharge, pain and burning with urination, pain and bleeding during sex and pelvic pain. 

Chlaymdia during pregnancy can lead to premature birth, membrane rupture or low birth weight. It can be passed from the mother to the baby during delivery if the mother has an active infection during pregnancy. This can lead to complications in the baby, like pneumonia or conjunctivitis. 

What to do: You should follow treatment as prescribed by your obstetrician. Treatment usually involves the use of antibiotics like azithromycin or doxycycline. Learn more about how chlamydia is treated. 

4. Gonorrhea 

Gonorrhea is also a sexually transmitted infection, however it is caused by Neisseria gonorrhoeae bacteria. It causes symptoms like a yellow discharge, pain or burning when urinating, urinary incontinence, vaginal itching or bleeding. 

Gonorrhea during pregnancy can lead to complications like spontaneous miscarriage, membrane rupture, premature labor, amniotic fluid infection or low birth weight.

In addition, gonorrhea can be transmitted to the baby during a vaginal delivery if it is left untreated. This can lead to neonatal conjunctivitis in the baby, blindness or a generalized infection. 

What to do: you are advised to see your obstetrician as quickly as possible to start treatment, which involves the use of antibiotics like penicillin, ofloxocin, or ciprofloxacin. 

5. Trichomoniasis

Trichomoniasis is a sexually transmitted infection, caused by Trichomonas vaginalis. It can occur in pregnancy following unprotected sex with someone who is infected. This infection causes symptoms like yellow or green discharge with a foul odor, redness, vaginal pain or itching, pain with urination, discomfort during sex, or the presence of scant vaginal bleeding. 

Trichomoniasis during pregnancy can increase the risk of premature labor or low birth weight, therefore it should be treated as quickly as possible.

What to do: You should consult your obstetrician to confirm a diagnosis and start treatment with an antibiotic like metronidazole. This antibiotic is usually taken for 3 to 7 days. 

6. Amniotic fluid

Yellow discharge can also be a sign of leaking amniotic fluid. However, amniotic fluid tends to have a more transparent, watery consistency that is either odorless or slightly sweet. It can leak in small quantities, like drips, or in large amounts. 

Leaking can happen during the first or second trimesters as a result of a vaginal infection, fetal membrane inflammation, drug or cigarette use, poor nutrition, or a short cervix. All of these can lead to premature rupture of the membranes, which should always be assessed by a gynecologist to avoid complications like miscarriage, premature birth or stillbirth. 

In addition, leaking that occurs after 37 weeks that is accompanied by other symptoms like regular contractions that increase in intensity and do not improve with repositioning my be a sign of labor.

What to do: You should proceed to the hospital as soon as possible if you suspect you are leaking amniotic fluid. The doctors will assess you and verify whether you have started to labor. Check-out more tips on how to recognize leaking amniotic fluid and when to go to the hospital. 

7. Mucus plug

The mucus plug is a substance produced by the body in the first months of pregnancy. Its main function is to prevent bacteria and other microorganisms from entering the uterus and impeding the development of the baby and the pregnancy. A mucus plug can be eliminated in pieces, and looks like a thin, white odorless discharge. However, it can also appear yellow, red or brown in color. 

Seeing parts of your mucus plug can be normal during pregnancy, but at the end of pregnancy, it may be a sign that the body is about to start to labor. Labor can start within hours, days or weeks of mucus plug elimination. Regardless, you should report any changes to discharge to your obstetrician.  

Learn more about what a mucus plug looks like and when you should notify your doctor. 

What to do: You should ensure you attend all prenatal appointments to verify whether you have any pregnancy-related risks. If you lose your mucus plug at the beginning of pregnancy, you should follow up with your obstetrician. If you lose your mucus plug at the end of pregnancy, you should monitor for other signs of labor, like bleeding, frequent and regular contractions, rupture of the amniotic sac and decreased fetal movements. If you notice these symptoms, proceed to the closest hospital immediately. 

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Updated by Tua Saude editing team, on August of 2022.
Our team made up of medical doctors and health professionals from various fields such as nursing, nutrition, physiotherapy, clinical analysis and pharmacy.