Viruses, bacteria, and other germs cause infections. You may be more likely to get an infection during pregnancy because your immune system is naturally suppressed. Many infections do not cause problems, but some can cause problems for you, your developing baby, or both. If you think you have an infection during pregnancy, it is important to talk to your healthcare provider as soon as possible.

Significant infections during pregnancy include:

Chickenpox (Varicella) —This is caused by a virus, which commonly affects children. Between 85% and 95% of pregnant women are immune to chickenpox. If you are immune to chickenpox, it is unlikely that you will get it again. About one woman in 2,000 will develop chickenpox during pregnancy. If you get chickenpox in the first 20 weeks of pregnancy, there is a very small chance (less than 1%) that your baby will be born with serious birth defects. If you get chickenpox around the time of delivery, your baby may be born with chickenpox infection. If this infection is treated, most babies have only a mild illness. Without treatment, up to 30% of infants die.

Chorioamnionitis —This is a rare but serious bacterial infection of the membranes surrounding the amniotic fluid and the baby. It usually starts because bacteria in your vagina or rectum move into your uterus where your developing baby is located. It is more likely to occur after the bag of water has broken. Chorioamnionitis happens in about 2% of births in the United States. In most cases, having this infection means your baby has to be delivered as soon as possible.

Cytomegalovirus (CMV) —This is a common viral infection that usually causes no symptoms. By age 30, about half of all adults in the United States have been infected with CMV. About 1% to 3% of pregnant women become infected for the first time with CMV. When a pregnant woman becomes infected, she can pass the virus on to her developing baby. In a small number of cases, this leads to serious illness in the newborn, lasting disabilities, and even death.

Group B Streptococcus (GBS) —This is a type of bacteria. Many people carry GBS, but do not become ill. One of every four or five pregnant women carries GBS in the rectum or vagina. A developing baby may come in contact with this bacteria before or during birth if the mother carries GBS, which can cause life-threatening infections in newborns. In pregnant women, GBS can cause bladder infections, infections of the uterus, and stillbirth.

Listeriosis —This is a rare infection caused by bacteria found in some contaminated foods. About 2,500 people get it each year. But pregnant women are more likely to get it than people who are not pregnant. Listeriosis can cause serious problems such as premature delivery , miscarriage , and severe illness or death of your newborn.

Parvovirus B19 Infection (Fifth Disease) —This common virus affects about 50% of all adults, causing a “slapped cheek” rash on the face. This infection happens most often in children. If you have contact with a person who has fifth disease, there are usually no serious problems for you or your developing baby. Sometimes, parvovirus B19 infection causes a developing baby to have severe anemia (low iron) or the woman may have a miscarriage.

Rubella (German Measles) —This mild childhood illness can cause serious birth defects in a developing fetus. For women who develop rubella in the first trimester of their pregnancy, there is a 25% chance that their baby will be born with one or more birth defects. These can include eye problems, hearing loss , heart defects, and mental retardation. With the widespread use of the rubella vaccine , major outbreaks of rubella no longer happen in the United States. Still, small outbreaks do happen. As many as 20% of childbearing women are at risk for this infection.

Sexually Transmitted Diseases (STDs) —Some STDs, such as genital herpes , chlamydia , and bacterial vaginosis , are commonly found in pregnant women. Other STDs, such as HIV and syphilis , are less commonly found in pregnant women. STDs can cause health problems such as:

Also, some STDs can be passed from you to your baby before, during, or after birth.

Toxoplasmosis —This infection is caused by a parasite (a type of germ). The parasite lives in the intestine of cats and is shed in cat feces, mainly into litter boxes and garden soil. Toxoplasmosis cause serious problems in a fetus when contracted by a pregnant woman. Each year in the US, approximately 400-1,000 babies are born with this condition, which can cause blindness, hearing loss, learning disabilities, miscarriage, and stillbirth.

Urinary Tract Infections (UTIs or Bladder Infections) —This bacterial infection is more common during pregnancy because of changes in the urinary tract. If the UTI goes untreated, it may lead to a kidney infection , which can cause early labor and low birth weight. If your doctor treats a urinary tract infection early, the UTI will not cause harm to your baby.

What are the risk factors for infection during pregnancy?
What are the symptoms of infection during pregnancy?
How are infections during pregnancy diagnosed?
What are the treatments for infection during pregnancy?
Are there screening tests to monitor for infection during pregnancy?
How can I reduce my risk of having an infection during pregnancy?
What questions should I ask my healthcare provider about infection during pregnancy?
Where can I get more information about infection during pregnancy?