What infections can affect pregnancy?

For the latest information on COVID-19 and pregnancy, visit CDC at https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/pregnant-people.html.

Infections that can affect the health of the pregnant woman, the pregnancy, and the baby after delivery include (but are not limited to):

• Bacterial vaginosis is the most common vaginal infection in women of reproductive age. It increases the risk of contracting sexually transmitted infections (STIs) and may play a role in preterm labor. The condition results from a change in the balance of bacteria that normally live in the vagina. Having unprotected sex and douching can increase the risk of bacterial vaginosis. The Centers for Disease Control and Prevention (CDC) recommends that pregnant women get tested for bacterial vaginosis if they have symptoms and get treated if necessary.¹
• Chlamydia infection during pregnancy is associated with an increased risk of preterm birth and its complications.² If the infection is present and untreated at the time of delivery, it can lead to eye infections or pneumonia in the infant.¹ In most hospitals, infants' eyes are routinely treated with an antibiotic ointment shortly after birth. The ointment can prevent blindness from exposure to chlamydia bacteria during delivery in case the pregnant woman had an undetected infection.
• Cytomegalovirus (CMV) is a common virus present in many body fluids that can be spread through close personal contact, such as kissing or sharing eating utensils, as well as sexual contact. The virus usually does not cause health problems, but once it is in a person's body, it stays there for life and can reactivate at different times. A pregnant woman may not even know she has the infection, and she may pass the virus on to her fetus, causing congenital CMV infection. Most infants with congenital CMV infection never show signs or have health problems. However, some infants have health problems such as hearing or vision loss, seizures, or intellectual disabilities that are apparent at birth or that develop later during infancy or childhood.³ Currently, routine screening for CMV during pregnancy is not recommended. Researchers are working on treatments for CMV and vaccines to try to prevent new infections during pregnancy and to reduce the risk of transmission to the infant.⁴Congenital CMV infection can be diagnosed by testing a newborn baby's saliva, urine, or blood. Treatment with antiviral drugs may decrease the risk of health problems and hearing loss in some infected infants.
• Fifth disease is caused by human parvovirus type B19. The virus causes a common childhood disease that spreads easily from person to person. Children who get it usually have a fever and a red rash on their cheeks. Parvovirus B19 usually does not cause problems for pregnant women or the fetus, but in rare cases, the woman might have a miscarriage or the fetus could develop anemia. There is no vaccine or treatment for fifth disease. You can reduce your chance of being infected with parvovirus B19 or infecting others by avoiding contact with people who have parvovirus B19 and by thoroughly and regularly washing your hands. Sometimes health care providers recommend testing pregnant women to see if they are immune to the virus already.
• Untreated gonorrhea infection in pregnancy has been linked to miscarriage, preterm birth and low birth weight, premature rupture of the membranes surrounding the fetus in the uterus, and infection of the fluid that surrounds the fetus during pregnancy. Gonorrhea can also infect an infant during delivery as it passes through the birth canal. If untreated, infants can develop eye infections and blindness. In most hospitals, infants' eyes are routinely treated with an antibiotic ointment shortly after birth to prevent eye problems from exposure to gonorrhea during delivery, in case the pregnant woman had an undetected infection. Treating gonorrhea as soon as it is detected in pregnant women reduces the risk of transmission.
• Group B streptococcus (GBS) can cause serious health problems in infants. But giving antibiotics during labor can prevent the spread of GBS, so it's important to get tested for the infection during pregnancy. Learn more about GBS and pregnancy.
• Pregnant women who get infected with genital herpes late in pregnancy have a high risk of infecting their fetus. The risk of infection is particularly high during delivery.¹ Herpes infections in newborns are serious and potentially life-threatening. Infection with the herpes virus during pregnancy or at the time of delivery can lead to brain damage, blindness, and damage to other organs. Rarely, herpes infection during pregnancy can lead to serious complications in the mother, including severe liver damage and possibly death.
  • If a pregnant woman has had genital herpes in the past, there are medications that she can take to reduce the chance that she will have an outbreak, which also reduces the risk to her fetus.
  • If a woman has active herpes sores when she goes into labor, the infant can be delivered by cesarean section to reduce the chance that the infant will come in contact with the virus.⁵
• If a woman is infected with hepatitis B virus (HBV) during pregnancy, the virus could infect her fetus. The likelihood of transmission depends on when during pregnancy the mother was infected. If the mother gets the infection later in her pregnancy, the risk that the virus will infect her fetus is quite high. If the infection occurs early in pregnancy, the risk of the virus infecting the fetus is much lower. For more information about Hep B during pregnancy, visit the Centers for Disease Control and Prevention (CDC) website. In infants, HBV can be serious and can lead to chronic liver disease or liver cancer later in life. In addition, infected newborns have a very high risk of becoming carriers of HBV and can spread the infection to others.
  • In some cases, if a woman is exposed to HBV during pregnancy, she may be treated with a special antibody to reduce the likelihood that she will get the infection.
  • All healthy infants should be vaccinated against HBV to give them lifelong protection.
  • Infants born to women with evidence of ongoing HBV infection (HBV surface antigen positive) should also receive hepatitis B hyperimmune globulin as soon as possible after birth.⁷
• Hepatitis C virus (HCV). CDC offers more information about HCV.
• HIV/AIDS. HIV can be passed from mother to infant during pregnancy before birth, at the time of delivery, or after birth during breastfeeding.⁶
• Human papillomavirus (HPV). CDC offers more information about HPV, including vaccine recommendations.
• Listeria or listeriosis is a serious infection usually caused by eating food  contaminated with a particular type of bacteria. Infection during pregnancy can lead to pregnancy loss, stillbirth, preterm birth, or life-threatening infection of the newborn. Listeriosis is most often associated with eating soft cheeses and raw milk, but recent outbreaks have been associated with fresh and frozen produce. Prevention recommendations include checking food labels to avoid eating unpasteurized cheese (made from raw milk) and other actions. Learn more about preventing listeria during pregnancy.
• Lyme disease is the most common vector-borne disease in the United States. It is caused by strains of the bacteria Borrelia and is transmitted through the bite of certain species of ticks. The National Institute of Allergy and Infectious Disease has more information on lyme disease. In addition, the CDC provides a handout about pregnancy and lyme disease (PDF 1.2 MB)
• Getting rubella (sometimes called German measles) during pregnancy can cause problems with the pregnancy as well as birth defects in the infant. Health care providers recommend that women get vaccinated against rubella before they get pregnant. Learn more about rubella and pregnancy.
• Syphilis may pass from an infected mother to her fetus during pregnancy. The infection has been linked to preterm birth, stillbirth, and, in some cases, death shortly after birth. Untreated infants who survive tend to develop problems in many organs, including the brain, eyes, ears, heart, skin, teeth, and bones. All pregnant women should be screened for syphilis during their first prenatal visit. Women considered to be high risk should be screened again in the third trimester.¹
• Toxoplasmosis is a disease caused by a parasite that can be present in cat feces or used cat litter. Cats get the parasite from eating small animals or birds. In humans, the disease is usually mild, but if the parasite passes from a pregnant woman to the developing fetus, it can cause intellectual disabilities, blindness, or other problems. Women who are trying to become pregnant or are pregnant can take steps to prevent exposure to the parasite, such as having someone else clean or change the cat litter box and wearing rubber gloves to handle cat litter or while gardening.
• Trichomoniasis. CDC offers more information about trichomoniasis.
• Zika is caused by a virus spread mainly by the bite of a certain type of mosquito, but it is also spread through sexual contact. Although its symptoms are usually mild, Zika infection during pregnancy can cause pregnancy loss and other pregnancy complications, as well as birth defects and other problems for the infant.

CDC provides additional information on infections during pregnancy and sexually transmitted infections (STIs) and pregnancy.