Patient information: Avoiding infections in pregnancy

Author
Vanessa A Barss, MD
Section Editor
Charles J Lockwood, MD
Deputy Editors
Leah K Moynihan, RNC, MSN
Barbara H McGovern, MD



Last literature review version 16.3: Wed Oct 01 00:00:00 GMT 2008 | This topic last updated: Mon Jan 29 00:00:00 GMT 2007 (More)


INTRODUCTION — Like all adults and children, pregnant women are at risk for developing viral and bacterial infections. Infections are a particular concern during pregnancy since some infections are more severe in pregnant women or increase the risk of harm to the fetus or newborn. Fortunately, women can take steps to decrease the chance of developing a potentially harmful illness during pregnancy.

HYGIENE — Good hygiene practices, such as frequent hand washing and avoiding contact with another person's saliva through shared foods, drinks, or utensils, can lessen a woman's chances of becoming infected with potentially harmful illnesses. Good hygiene is particularly important for pregnant women whose work puts them in contact with large groups of children, as in day care centers or schools. Hygiene is also important for mothers of young children, because some potentially harmful infections, such as cytomegalovirus, are more prevalent in young children.

Hand washing is an essential and very effective way to prevent the spread of infection. Hands should be wet with water and plain or antimicrobial soap and rubbed together for 15 to 30 seconds. Special attention should be paid to the fingernails, between the fingers, and the wrists. Hands should be rinsed thoroughly and dried with a single use towel.

Alcohol-based hand rubs are a good alternative for disinfecting hands if a sink is not available. Hand rubs should be spread over the entire surface of hands, fingers, and wrists until dry, and may be used several times. Hand rubs are available as a liquid or wipe in small, portable sizes that are easy to carry in a pocket or handbag. When a sink is available, visibly soiled hands should be washed with soap and water.

Hands should be washed before and after preparing food and eating, after going to the bathroom, after changing a diaper or assisting a child with toileting, after handling garbage or dirty laundry, after touching animals or pets, and after gardening.

IMMUNIZATION — A person whose body has developed antibodies to an infection is said to be immune to that infection. Antibodies are proteins that develop in response to infection or vaccination, which can prevent that infection from developing or recurring.

Immunizations should generally be given at least one month before a woman becomes pregnant to avoid exposing the baby to the vaccine. Inactivated vaccines, toxoids, and immune globulin preparations are not known to be harmful to mother or baby during pregnancy. These vaccines are given during pregnancy if there is a high risk of exposure to a particular infection and the infection is hazardous to mother or fetus.

Live vaccines, which contain a weakened form of live bacteria or virus, are not strong enough to make a healthy adult sick, but they do have the theoretical potential for infecting the fetus. For this reason, live vaccines are not typically given during pregnancy unless the woman is at substantial risk of contracting an infection associated with serious complications or death. However, to date there is no evidence that pregnant women who inadvertently received the live vaccine for rubella (often called German measles) have higher rates of birth defects.

Immunizations before pregnancy — Any woman who is planning to become pregnant should talk with her health care provider about the need for immunization against measles, mumps, and rubella, and chicken pox (varicella).

Measles, mumps, and rubella — Contracting any of these conditions can cause serious problems during pregnancy. Rubella (German measles) is the infection of greatest concern for the fetus. Rubella is associated with an increased risk of miscarriage and can also cause a congenital syndrome in the newborn that may include deafness, visual problems, cardiac defects, neurologic abnormalities, and mental retardation. Measles can increase the chance of preterm birth, and, possibly, of miscarriage. Mumps in the first trimester appears to be associated with an increased risk of fetal death.

Most American women of childbearing age are immune to these conditions because of childhood vaccination. The measles, mumps, rubella (MMR) vaccine is a single vaccine that provides immunity to all three infections. Since MMR is a live vaccine, women should receive MMR before becoming pregnant and should then avoid becoming pregnant for 28 days. The vaccine can be given safely to postpartum women who are breastfeeding and to the children of pregnant women.

Varicella (chickenpox) — Chickenpox can cause problems throughout a pregnancy. If a woman has chickenpox during the first 20 weeks of pregnancy, there is a small risk (2 percent) that her infant will develop varicella syndrome, which includes abnormally small limbs and head, mental retardation, scarring of the skin, and eye defects. If a mother becomes infected around the time of delivery, the infection can be passed to the newborn. Women with chickenpox during pregnancy experience the usual discomforts (itching) but also are at risk for serious complications, such as pneumonia.

The varicella vaccine provides immunity to chickenpox. Because it is a live vaccine, it should be given at least one month before pregnancy. Any woman who is already pregnant and is not immune to varicella should talk with her healthcare provider about the need for family members, such as small children, to receive routine varicella immunization. Because the vaccine uses live virus, there is a very small risk that the pregnant woman could become infected from exposure to a recently vaccinated child. However, this risk may be outweighed by the risk of the woman becoming infected if the family member were to develop chickenpox.

Human papillomavirus — The human papillovirus (HPV) vaccine does not contain live virus. It is recommended for nonpregnant girls and women 9 to 26 years of age. It is not recommended for pregnant women since it is a new vaccine and its safety in pregnancy has not been studied.

Immunization during pregnancy

Influenza (flu) — Because the flu can cause serious medical complications in pregnant women, vaccination against the flu is recommended for all women who will be pregnant during influenza season, regardless of their stage of pregnancy. (See "Patient information: Influenza"). Women can safely breastfeed after receiving the vaccine.

Tetanus and diphtheria — Combined tetanus and diptheria toxoids should be given to pregnant women who have not completed the three dose primary immunization series. Those who have not received a tetanus and diptheria immunization within the past 10 years should receive a booster dose. Administration of a combined tetanus, diphtheria, and pertussis immunization after delivery may be another option.

Immunizations for high risk groups — In addition to routine immunizations, some pregnant women should consider additional vaccines.

Hepatitis A — Hepatitis A is a common cause of hepatitis that can rarely become severe. The hepatitis A virus can be passed from a pregnant woman to her fetus.

The hepatitis A vaccine is given to pregnant women at risk for developing the illness, including: travelers to countries where hepatitis A is common; injection and non-injection illegal drug users; partners of bisexual men; people with chronic liver disease; adults with blood clotting factor disorders; adults with an occupational risk for infection; day care center staff; personnel in long-term care facilities; and food handlers.

Hepatitis B — Hepatitis B is a serious infection that causes inflammation of the liver. It can damage the liver in people who are infected. The hepatitis B vaccine is given in a series of three injections. The vaccine is recommended for pregnant women who started the immunization series before becoming pregnant and to those at high risk for acquiring hepatitis B during pregnancy. (See "Patient information: Hepatitis B").

Poliomyelitis — Poliomyelitis (polio) is caused by a virus that can produce fever, paralysis, and loss of muscle. Polio has been eliminated from the Americas and most other developed countries, but a number of other countries are still affected by large outbreaks. Pregnant women should avoid travel, if possible, to areas where the disease is present. If travel is not avoidable, pregnant women should be immunized with the inactivated virus vaccine. A woman who has been immunized against polio in the past may require a booster vaccine if she is at risk of exposure to polio. (See "Patient information: General travel advice").

Pneumococcus — Pneumococci are bacteria that are the leading cause of pneumonia and a number of other infections, including otitis media (ear infection) and meningitis. Women at high risk for pneumococcal infections should receive the pneumococcal vaccine. Ideally, the vaccine is given prior to pregnancy, although it appears to be safe when given in the second and third trimesters (there is little information about the safety of the vaccine during the first trimester).

Women at high risk for pneumococcal infection include:

Women with chronic illness including diseases of the heart or lungs, diabetes, alcoholism, and chronic liver failure
Women with conditions that cause leakage of cerebrospinal fluid (the fluid that circulates around the brain and spinal cord)
Women with an impaired immune system
Women living in special environments including long term care facilities, prisons, and institutions for the developmentally disabled
Women from certain ethnic groups (eg, Alaskan natives or certain American Indian populations)
Yellow fever — Yellow fever is a viral disease transmitted by mosquitoes. It is associated with liver and kidney damage and hemorrhage, and often leads to death. The disease occurs in tropical regions of South America and sub-Saharan Africa; these areas should be avoided during pregnancy, if possible. If travel is not avoidable and the risk of yellow fever is high, immunization with a live virus vaccine may be considered.

Some studies of women who received the yellow fever vaccine during pregnancy have shown an increased risk of miscarriage and a low level of yellow fever affecting the newborn. However, other studies have found no increase in pregnancy complications. Women traveling to locations where the immunization is required but the risk of yellow fever is low may be able to get permission to waive the vaccine. (See "Patient information: Immunizations for travel").

Other immunizations — Vaccines against a number of other infections are available, including cholera, meningococcus, plague, rabies, Japanese encephalitis, typhoid, smallpox, and Haemophilus influenzae B. A healthcare provider can determine the risk of exposure to these illnesses and the need for immunization.

INFECTIONS — Several infectious diseases can cause problems in pregnancy although there are currently no vaccines available. These are best avoided by practicing good hygiene and avoiding direct contact with infected individuals (although this may prove difficult in some cases).

Parvovirus B19 — Parvovirus B19 infection, also known as "fifth disease," is a common childhood viral infection. B19 may cause mild illness in adults with a normal immune system. Symptoms of B19 infection include joint pain and bodywide symptoms such as fatigue and malaise. In children, a rash may appear on the face, trunk, arms, and legs. The rash on the face can be intensely red as though the child had been slapped (a "slapped cheek" appearance). The illness generally resolves on its own.

The first B19 infection occurs infrequently during pregnancy because most people have been exposed to the virus during childhood. In those who are infected, it can rarely cause miscarriage, a low fetal blood count, or fetal heart problems.

Ideally, pregnant women who have never had this infection should avoid contact with adults or children who may be infected. However, this may be difficult for women with jobs that involve groups of children, such as school teachers and day care center employees. In these situations, frequent hand washing and avoiding shared food or drinks can help to prevent infection. A pregnant woman who works with small children may want to be tested for B19 to determine if she has been exposed previously, and is therefore immune; a result showing immunity can be reassuring.

Since the infection is common during childhood, many women are already immune. If a pregnant woman is exposed to parvovirus B19, blood testing is recommended to determine her immune status. If blood testing is initially negative, it may be repeated three to four weeks later to confirm that the woman has not developed the infection. Women who become infected are monitored closely for signs of complications.

Cytomegalovirus infection (CMV) — Cytomegalovirus (CMV) is a common virus that infects 50 to 85 percent of adults in the United States. The virus is transmitted by sexual contact or other close contact with an infected person's saliva, urine, or other body fluids. Transmission is higher in households with young children and in day care centers.

CMV infection may cause few symptoms in the pregnant woman, including mild illness with a low-grade fever. If a woman has a CMV infection during pregnancy, she may pass CMV to her fetus during pregnancy or delivery, or to her infant through breast milk. Fetuses infected with CMV may or may not have symptoms at birth. Some infected fetuses with no symptoms at birth develop hearing, vision, and neurologic problems later in childhood.

Medications to treat CMV in newborns are currently being studied. Vaccines against CMV are also being tested, but are not yet available. Good hygiene practices, especially hand washing, are encouraged to decrease the chances of developing CMV infection during pregnancy. Guidelines from the Centers for Disease Control and Prevention (CDC) are available at www.cdc.gov/ncidod/diseases/cmv.htm, and include the following:

Practice good personal hygiene throughout pregnancy, especially hand washing with soap and water after contact with diapers or oral secretions (particularly with a child who is in day care). Do not share food or utensils.
Women who develop a low-grade fever, malaise, and fatigue during pregnancy should be evaluated for CMV infection and counseled about the possible risks to the unborn child.
The benefits of breastfeeding outweigh the minimal risk of acquiring CMV from breastmilk. (See "Patient information: Breastfeeding").
Toxoplasmosis — Toxoplasmosis is a parasitic illness that usually causes no symptoms. It can affect the fetus if the mother develops infection during pregnancy. Although the rate of fetal infection is highest if the mother is infected during the third trimester, the outcome for the baby is most severe if the maternal infection occurs during the first trimester.

Most infants with congenital toxoplasmosis (70 to 90 percent) have no symptoms or abnormalities at birth. However, some have fever, rash, an enlarged liver and spleen, a small head (microcephaly), water on the brain (hydrocephalus), or seizures. If the infant appears normal at birth but has congenital toxoplasmosis and is not treated, late findings can arise, the most common of which is inflammation of the eye that can result in vision loss in the affected eye.

House cats can carry the toxoplasmosis parasite in their feces, but the more common way to become infected is by consuming undercooked meat. Pregnant women should avoid all rare and uncooked meat. While it is not clear that changing a cat litter box is a major risk for becoming infected with toxoplasmosis, it is probably reasonable for pregnant women to have someone else change the box or to wear gloves and then wash hands carefully afterwards. It is also important to wear gloves while gardening and to wash hands after working in the yard since the soil can be contaminated by cat feces.

Listeria — Listeria is a bacterial infection that can cause fetal death, premature birth, or newborn infection. It can be passed from an infected mother to her fetus through the blood. Signs and symptoms of Listeria include fever, chills, and back pain; a nonspecific flu-like illness is the most common symptom.

Most people who become infected with Listeria have eaten food that is contaminated. Contaminated foods do not always appear rotten or spoiled and it is not possible to know, based upon appearance or smell, if a food is safe. For this reason, women who are pregnant are advised to avoid foods that could contain Listeria (see "Food precautions" below).

AVOIDING EXPOSURE TO INFECTIOUS DISEASES — In addition to immunization and attention to hygiene, pregnant women should consider measures to avoid exposure to infectious agents known to cause problems with pregnancy.

Travel — Avoiding travel to high risk locations is one effective approach. In some parts of the world, polio, yellow fever, and malaria are still common. Women who are planning international travel during pregnancy should consult with a travel clinic about the safety of the planned destination. (See "Patient information: General travel advice").

Immunizations for family — Children and other family household members should be up to date with their immunizations; this decreases a pregnant woman's risk of exposure to infections during pregnancy.

Insect borne illnesses — The Centers for Disease Control and Prevention has advised pregnant women to take precautions that reduce the risk of acquiring mosquito-borne infections (eg, West Nile virus). Mosquito bites can be prevented through use of protective clothing, avoiding the outdoors when mosquitoes are most active (dawn and dusk), and use of DEET-based insect repellents. . Updated information regarding mosquito repellents is available from the CDC at www.cdc.gov/ncidod/dvbid/westnile/RepellentUpdates.htm. (See "Patient information: West Nile virus infection").

Animal borne illnesses — Women who are pregnant or planning pregnancy should avoid contact with all rodents. Precautions about handling pets and laboratory animals should be discussed with a healthcare provider. (See "Patient information: Animal bites").

Sexually transmitted infections — Some common sexually transmitted diseases include gonorrhea, syphilis, herpes, HIV, chlamydia, hepatitis, trichomonas, and genital warts. Pregnant women should minimize their risk of sexually transmitted diseases by avoiding sex with multiple partners or men who have multiple partners. Pregnant women should use a condom when having sex with a partner who is or may be infected with a sexually transmitted disease, although condoms are not 100 percent effective in preventing transmission of these diseases. (See "Patient information: Genital herpes" and see "Patient information: Gonorrhea" and see "Patient information: Chlamydia" and see "Patient information: Condyloma (genital warts) in women").

Food precautions — The following precautions have been recommended for all consumers by the Food Safety and Inspection Services (http://www.fsis.usda.gov/) and the Centers for Disease Control and Prevention.

Do not drink raw (unpasteurized) milk or foods that contain unpasteurized milk.
Wash raw fruits and vegetables thoroughly before eating.
Keep the refrigerator temperature at 40ºF (4.4ºC) or lower; the freezer at 0ºF (-17.8ºC) or lower.
Use precooked, perishable, or ready-to-eat food as soon as possible.
Keep raw meat, fish, and poultry separate from other food that will not be cooked and away from cooked foods and ready-to-eat foods.
Wash hands, knives, and cutting boards after handling uncooked food, including produce and raw meat, fish, or poultry.
Thoroughly cook raw food from animal sources to a safe internal temperature: ground beef 160ºF (71ºC); chicken 170ºF (77ºC); turkey 180ºF (82ºC); pork 160ºF (71ºC).
Seafood should be cooked thoroughly to minimize the risk of food poisoning. Eating raw fish (eg, sushi) poses a risk for a variety of parasitic worms (in addition to the risks associated with organisms carried by food handlers). Freezing kills some, although not all, harmful microorganisms. Raw fish that is labeled "sushi-grade" or "sashimi-grade" has been frozen.
Cook chicken eggs thoroughly, until the yolk is firm.
Refrigerate foods promptly after purchase, preparation, or eating.
Never leave cooked foods at room temperature for more than two hours (one hour if the room temperature is above 90ºF or 32ºC).
The following additional recommendations were made for pregnant women and those who have a weakened immune system:

Do not eat hot dogs, luncheon meats, bologna, or other delicatessen meats unless they are reheated until steaming hot; avoid the use of the microwave oven since uneven cooking may occur.
Avoid getting fluids from hot dog packages on other foods, utensils, and food preparation surfaces. In addition, wash hands after handling hot dogs, luncheon meats, delicatessen meats, and raw meat, chicken, turkey, or seafood or their juices.
Do not eat salads made in the store such as ham salad, chicken salad, egg salad, tuna salad, or seafood salad.
Do not eat soft cheeses such as feta, Brie, and Camembert, blue-veined cheeses, or Mexican-style cheeses such as queso blanco, queso fresco, or Panela unless they have a label that clearly states that the cheese is made from pasteurized milk.
Do not eat refrigerated pâtés or meat spreads. Canned or shelf-stable products may be eaten.
Do not eat refrigerated smoked seafood unless it has been cooked. Refrigerated smoked seafood, such as salmon, trout, whitefish, cod, tuna or mackerel, is most often labeled as "nova-style," "lox," "kippered," "smoked," or "jerky." The fish is found in the refrigerator section or sold at deli counters of grocery stores and delicatessens. Canned or shelf-stable smoked seafood may be eaten.
TREATMENT OF INFECTIONS — The safety and availability of treatment for infection in pregnant women depends upon the type of infection and risk of harm (from the treatment or infection) to the woman and her fetus. Pregnant women and their families are advised to discuss any concerns about infections or treatments with a healthcare provider.

WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:


A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)


Centers for Disease Control and Prevention (CDC)
Toll-free: (800) 311-3435
(http://www.cdc.gov/)


Infectious Diseases Society of America
(http://www.idsociety.org/)







REFERENCES


ACOG Committee Opinion. Immunization during pregnancy. Obstet Gynecol 2003; 101:207.
Kroger, AT, Atkinson, WL, Marcuse, EK, Pickering, LK. General recommendations on immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2006; 55:1.
Revised ACIP recommendation for avoiding pregnancy after receiving a rubella-containing vaccine. MMWR Morb Mortal Wkly Rep 2001; 50:1117.
Pastuszak, AL, Levy, M, Schick, B, et al. Outcome after maternal varicella infection in the first 20 weeks of pregnancy. N Engl J Med 1994; 330:901.
Tan, MP, Koren, G. Chickenpox in pregnancy: revisited. Reprod Toxicol 2006; 21:410.
Bar-Oz, B, Levichek, Z, Moretti, ME, et al. Pregnancy outcome following rubella vaccination: a prospective controlled study. Am J Med Genet 2004; 130A:52.


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