Most common infections that occur during pregnancy, such as those of the skin, urinary tract, and respiratory tract, cause no serious problems. However, some infections can be passed to the fetus before or during birth and damage the fetus or cause a miscarriage Miscarriage A miscarriage is the loss of a fetus before 20 weeks of pregnancy. Miscarriages may occur because of a problem in the fetus (such as a genetic disorder or birth defect) or in the woman (such... read more or premature birth Preterm Labor Labor that occurs before 37 weeks of pregnancy is considered preterm. Babies born prematurely can have serious health problems. The diagnosis of preterm labor is usually obvious. Measures such... read more . Also, whether taking antibiotics and other antimicrobial drugs is safe during pregnancy is a concern.
Sexually transmitted infections Overview of Sexually Transmitted Infections (STIs) Sexually transmitted infection (STI) refers to an infection that is passed through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with an infected partner... read more that can cause problems include the following:
Chlamydial infection Chlamydia and Other Nongonococcal Infections Chlamydial infections include sexually transmitted infections of the urethra, cervix, and rectum that are caused by the bacteria Chlamydia trachomatis. These bacteria can also infect... read more may cause preterm labor Preterm Labor Labor that occurs before 37 weeks of pregnancy is considered preterm. Babies born prematurely can have serious health problems. The diagnosis of preterm labor is usually obvious. Measures such... read more and premature rupture of the membranes Prelabor Rupture of the Membranes (PROM) Prelabor rupture of the membranes is the leaking of amniotic fluid from around the fetus at any time before labor starts. After the membranes rupture, labor often soon follows. If labor does... read more . It can also cause eye inflammation (conjunctivitis) in newborns Conjunctivitis in Newborns Conjunctivitis is inflammation of the conjunctiva, the membrane that lines the eyelid and covers the white of the eye. Conjunctivitis is caused by bacteria, viruses, or a reaction to chemicals... read more .
Syphilis Syphilis Syphilis is a sexually transmitted infection caused by the bacteria Treponema pallidum. It can occur in three stages of symptoms, separated by periods of apparent good health. Syphilis... read more can be transmitted from a mother to the fetus through the placenta. Syphilis in the fetus Syphilis in Newborns Syphilis is an infection caused by the bacteria Treponema pallidum. It causes serious problems in infants infected before birth. Syphilis is caused by bacteria. Serious complications... read more can cause several birth defects and cause problems in the newborn. Pregnant women are routinely tested for syphilis early in the pregnancy. Usually, treatment of syphilis during pregnancy cures both mother and fetus.
Human immunodeficiency virus Human Immunodeficiency Virus (HIV) Infection in Children and Adolescents Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and makes people more vulnerable to other infections and some cancers... read more (HIV) infection is transmitted to the fetus in about one fourth to one third of pregnancies if women who have the infection are not treated. Experts recommend that women with HIV infection take antiretroviral drugs during pregnancy. If women take a combination of antiretroviral drugs, the risk of transmitting HIV to the fetus can be reduced to as low as 1%. For some women with HIV infection, cesarean delivery, planned in advance, may further reduce the risk of transmitting HIV to the baby. Pregnancy does not seem to speed up the progression of HIV infection in women.
Genital herpes Herpes Simplex Virus (HSV) Infections Herpes simplex virus infection causes recurring episodes of small, painful, fluid-filled blisters on the skin, mouth, lips (cold sores), eyes, or genitals. This very contagious viral infection... read more can be transmitted to the baby during a vaginal delivery. Babies who are infected with herpes Herpes Simplex Virus (HSV) Infection in Newborns Herpes simplex virus infection usually causes only annoying, recurring blisters in healthy adults but can cause severe infection in newborns. Newborns may become infected at birth or after birth... read more can develop a life-threatening brain infection called herpes encephalitis. A herpes infection in babies can also damage other internal organs and cause skin and mouth sores, permanent brain damage, or even death. If women develop herpes sores in the genital area late in pregnancy or if herpes first develops during late pregnancy, women are usually advised to give birth by cesarean delivery, so that the virus is not transmitted to the baby. If no sores are present and herpes develops earlier, the risk of transmission is very low, and vaginal delivery is possible.
Zika virus infection Zika Virus Infection Zika virus infection is a mosquito-borne viral infection that typically causes no symptoms but can cause fever, rash, joint pain, or infection of the membrane that covers the white of the eye... read more in a pregnant woman can cause the baby to have a small head (microcephaly Microcephaly Microcephaly is an abnormally small head. Often the head is small because the brain is small and abnormally developed. Microcephaly can be caused by many disorders, including genetic abnormalities... read more ). The head is small because it does not develop normally. Zika virus infection can also cause eye abnormalities in the baby. The Zika virus is spread by mosquitoes, but it can also be spread through sexual intercourse, through blood transfusions, and from a pregnant woman to her baby before or during birth.
Infections that are not transmitted sexually and that can cause problems include the following:
German measles (rubella Rubella Rubella is a contagious viral infection that typically causes in children mild symptoms, such as joint pain and a rash. Rubella can cause death of a fetus or severe birth defects if the mother... read more ) can cause problems, particularly inadequate growth before birth (small for gestational age Small-for-Gestational-Age (SGA) Newborns A newborn who weighs less than 90% of newborns of the same gestational age at birth (below the 10th percentile) is considered small for gestational age. Newborns may be small because their parents... read more ), cataracts, birth defects of the heart Overview of Heart Defects About one in 100 babies is born with a heart defect. Some are severe, but many are not. Defects may involve abnormal formation of the heart's walls or valves or of the blood vessels that enter... read more , hearing loss, and delayed development.
Cytomegalovirus infection Cytomegalovirus (CMV) Infection Cytomegalovirus infection is a common herpesvirus infection with a wide range of symptoms: from no symptoms to fever and fatigue (resembling infectious mononucleosis) to severe symptoms involving... read more can cross the placenta and damage the fetus’s liver and brain, and the fetus may not grow as much as expected.
Chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more (varicella) increases the risk of a miscarriage. It may damage the eyes of the fetus or cause defects of the limbs Introduction to Birth Defects of the Face, Bones, Joints, and Muscles Birth defects, also called congenital anomalies, are physical abnormalities that occur before a baby is born. "Congenital" means "present at birth." Birth defects of the face and limbs are fairly... read more , blindness, or intellectual disability. The fetus’s head may be smaller than normal (microcephaly).
Toxoplasmosis Toxoplasmosis Toxoplasmosis is infection caused by the protozoan parasite Toxoplasma gondii. Infection occurs when people unknowingly ingest toxoplasma cysts from cat feces or eat contaminated meat... read more , a protozoal infection, may cause a miscarriage Miscarriage A miscarriage is the loss of a fetus before 20 weeks of pregnancy. Miscarriages may occur because of a problem in the fetus (such as a genetic disorder or birth defect) or in the woman (such... read more , death of the fetus, and serious birth defects.
Listeriosis Listeriosis Listeriosis is infection caused by the gram-positive bacteria Listeria monocytogenes, usually when contaminated food is eaten. People may consume the bacteria in contaminated dairy products... read more , a bacterial infection, increases the risk of preterm labor Preterm Labor Labor that occurs before 37 weeks of pregnancy is considered preterm. Babies born prematurely can have serious health problems. The diagnosis of preterm labor is usually obvious. Measures such... read more , miscarriage Miscarriage A miscarriage is the loss of a fetus before 20 weeks of pregnancy. Miscarriages may occur because of a problem in the fetus (such as a genetic disorder or birth defect) or in the woman (such... read more , and stillbirth Stillbirth Stillbirth is death of a fetus after 20 weeks of pregnancy. Stillbirth may result from a problem in the woman, placenta, or fetus. Doctors do blood tests to try to identify the cause of a stillbirth... read more . Newborns may have the infection, but symptoms may be delayed until several weeks after birth.
Bacterial infections of the vagina (such as bacterial vaginosis Bacterial Vaginosis (BV) Bacterial vaginosis is a common condition that occurs when the balance of bacteria in the vagina (vaginal microbiome) is altered. Bacterial vaginosis causes a thin, yellow-green or gray discharge... read more ) may lead to preterm labor or premature rupture of the membranes Prelabor Rupture of the Membranes (PROM) Prelabor rupture of the membranes is the leaking of amniotic fluid from around the fetus at any time before labor starts. After the membranes rupture, labor often soon follows. If labor does... read more containing the fetus.
Urinary tract infections Overview of Urinary Tract Infections (UTIs) In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present. The tube that carries urine from the bladder out of the body (urethra) contains no bacteria... read more increase the risk of preterm labor and premature rupture of the membranes containing the fetus.
Hepatitis Overview of Hepatitis Hepatitis is inflammation of the liver. (See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.) Hepatitis is common throughout the world. Hepatitis can be Acute (short-lived) read more may be transmitted sexually but is often transmitted in other ways. Thus, it is not typically considered a sexually transmitted infection. Hepatitis in a pregnant woman Hepatitis Some liver disorders occur only during pregnancy. Others (such as gallstones, cirrhosis, or hepatitis) may have been present before the pregnancy, or they may occur coincidentally with the pregnancy... read more can increase the risk of premature birth Preterm (Premature) Newborns A preterm newborn is a baby delivered before 37 weeks of gestation. Depending on when they are born, preterm newborns have underdeveloped organs, which may not be ready to function outside of... read more . It can also be transmitted from the mother to the baby during delivery, causing problems.
Treatment of Infections During Pregnancy
Sometimes drugs, depending on the balance of benefits and risks
To determine whether to treat pregnant women with antimicrobial drugs, doctors weigh the risks of using the drug against the risks of the infection.
Some antibacterial drugs Overview of Antibiotics Antibiotics are drugs used to treat bacterial infections. They are not effective against viral infections and most other infections. Antibiotics either kill bacteria or stop them from reproducing... read more , such as the penicillins, cephalosporins, and drugs related to erythromycin (called macrolides), are generally considered safe for use during pregnancy.
Other antibacterial drugs, including tetracyclines and fluoroquinolones, may cause problems in the fetus (see table Some Drugs That Can Cause Problems During Pregnancy Some Drugs That Can Cause Problems During Pregnancy* ).
Doctors also consider whether treatment is likely to have any benefits. For example, if women have bacterial vaginosis but no symptoms and if the pregnancy is not considered high-risk, treating bacterial vaginosis is not known to have any benefits.