(Note: Please refer to ST1 chart for some additional diseases.)

Name of Disease

Presenting Symptoms

Incubation Period

Mode of Transmission

Usual Course

Important Facts in Pregnancy

Chicken pox (varicella)

Low-grade fever, followed by rash beginning on face and scalp in 24 hours, spreading quickly to trunk

12-18 days

Droplets or aerosols from vesicle fluid; secretions of the upper respiratory tract of infected individuals. Virus is disseminated across the placenta.

After initial rash, lesions appear for approximately 5 days; intense pruritus is characteristic. Antibodies appear after 5 days. Crusted lesions are not infectious.

Symptoms are more pronounced in adults; 14% of infected pregnant women develop varicella pneumonia. Relatively low frequency of anomalies in first half of pregnancy. Most extreme manifestation is varicella embryopathy, reported in approximately 1%-2%.^* Preterm labor occurs in 14%.

Infection 5 days before and 2 days after delivery may result in neonatal disease.

Fifth disease (parvovirus B19)

Mild prodrome with low-grade fever, headache, malaise, often unnoticed, followed by hallmark “slapped-cheek” rash. Adults may present with symmetrical arthralgias.

4-20 days

Probably by droplets from oral or nasal secretions. Virus found in upper respiratory tract secretions and blood several days before symptoms. Placental transmission possible in primary maternal infections.

In adults, most common course is malaise and arthralgia; rash may not be evident. Rash, if present, usually resolves in about 3 weeks. Patients with underlying hemoglobinopathy may have a transient aplastic crisis.

Chance of infection of a susceptible pregnant woman from an infected household member is 50%-90%; daycare or classroom exposure 20%-30%. Fetal risk is greatest in 1st trimester maternal illness, rate of maternal-fetal transmission is 5%-15%. Fetal hydrops results, leading to an aplastic anemia and congestive heart failure. No structural anomalies seen.

Measles (rubeola)

Fever, malaise, coryza, conjunctivitis, photosensitivity; generalized maculopapular rash; Koplik’s spots.^†

10-12 days

Respiratory droplets; virus can cross the placenta.

Typical rash begins on face and neck, spreading to trunk and extremities, lasting approximately 5 days, receding in order of appearance. Disease associated with an increase in maternal mortality during pregnancy primarily because of pulmonary complications.

Infected pregnant women need close monitoring for hepatitis, encephalitis, and pneumonia. Slight increase in preterm delivery and spontaneous abortions. Congenital anomalies not significant. Neonatal measles develops within 10 days of delivery in infants of acutely infected mothers.

Rubella (German measles)

Half of affected individuals have no symptoms. Simultaneous occurrence of low-grade fever, mild upper respiratory tract infection, and macular pruritic rash.

14-18 days

Respiratory transmission; virus shed from 1 week before to 3 weeks after acute illness.

Rash fades within 1-3 days of onset. Posterior cervical and occipital adenopathy may be the only presenting symptoms, peaking at the time of rash. Usual recovery is 3-4 days. Major complication is acute polyarthralgia, possibly persisting for days to weeks.

Timing of gestation is most critical in the fetal/natal course. Infection as early as 12 days after LMP may cause fetal infection. Maternal infection before 16 weeks may lead to ocular, cardiac, and CNS systems being adversely affected. Approximately 20% of exposed individuals, even as late as exposure in the 6 months of gestation, have manifestations 10-20 years later.

Toxoplasmosis (Toxoplasma gondii)

No real course of disease is noted in immune-intact individuals.

Manifestations are seen in immunecompromised individuals and the fetus.

No real incubation period. After inoculation or ingestion, the organism invades cells directly or is affected by phagocytosis.

Ingested in undercooked meat; oocysts in cat feces; blood transfusion; placental transmission during maternal parasitemia.

Course of infection is influenced by size of inoculation, virulence of organism, and immune status of the patient. For immunosuppressed individuals and the fetus, infection may result in massive tissue destruction in multiple organs, primarily the brain and eye in the fetus.

Acute maternal infection is necessary for fetal/neonatal manifestations; 40% of infants born to acutely infected mothers have signs of infection. Congenital infection is most likely in 3rd trimester exposure. Less than 40% of infants whose mothers are infected develop toxoplasmosis complications. Wide range of clinical presentations.

Zika virus

Eighty percent will have no symptoms; low-grade fever, maculopapular rash (often starting on face and spreading to rest of the body); myalgia/arthralgia; conjunctivitis.

3-14 days

Primarily via two types of mosquitos: Aedes aegypti and Aedes albopictus. It can also be sexually transmitted.

In both adults and children, acute onset fever occurs with 2 weeks of infection, along with muscle and joint pain. If rash develops, it will often begin 2-3 days following initial symptom onset. Symptoms resolve on their own within 5-7 days. Zika virus infection may not result in any discernible symptoms; in planning for any attempts to become pregnant, the starting point for measuring the length of time from “symptom onset” is also identified as the last known possible exposure to the virus, in the absence of symptoms. Because viral RNA has been detected in serum samples from women up to 46 days after initial symptom onset, it is recommended that women wait at least 8 weeks before trying to become pregnant. In general, viral RNA has been detected in semen samples for up to 6 months after symptom onset in men, so it is recommended that condoms be utilized during this period.

There is no vaccine available against Zika virus, and no available treatment or cure. Education about preventing exposure is key. Pregnant women, or women thinking of becoming pregnant, should avoid travel to areas where Zika is occurring, wear clothing that covers as much skin as possible, and pretreat clothing and bed sheets with insect repellant (permethrin, which is safe to use during pregnancy). Zika can be transmitted from mother to fetus during pregnancy and is known to cause problems with fetal development, including microcephaly, eye defects, and hearing loss. Infection during the 1st trimester poses the highest risk for fetal congenital anomalies. Women presenting with symptoms should be tested for the virus. Because of the absence of symptoms in most cases, all asymptomatic pregnant women at risk for Zika infection (recent travel to an area where Zika is prevalent, or if their partner has traveled to an area) should also be tested. Even in cases where the woman tests negative for the virus, serial ultrasounds are suggested. Symptoms can be treated with OTC pain medication, warm compresses, hydration, and rest. Zika occurs in areas where other, similarly presenting diseases such as dengue also occur; NSAIDs should be avoided in symptomatic pregnant women prior to confirmation of Zika, as they increase the risk of hemorrhage if taken during dengue infection, a communicable disease that closely mirrors Zika and occurs in the same areas as Zika.^‡

LMP, last menstrual period; CNS, central nervous system; OTC, over-the-counter; NSAIDs, nonsteroidal anti-inflammatory drugs.

^* Varicella embryopathy has multiple anomalies, including limb hypoplasia, cutaneous scarring, microcephaly, psychomotor retardation, malformed digits, and ocular abnormalities.

^† Koplik’s spots are blue-gray specks with a red base, developing across from the 2nd molars on the buccal mucosa.

^‡ The most comprehensive and current directory of Zika-related resources can be found at the U.S. Department of Health and Human Services’s Disaster Information and Management Research Center (DIMRC) page. Unlike the more widely known Centers for Disease Control and Prevention (CDC) resource site, DIMRC provides access to the most recently published research literature available, along with links to relevant social media accounts, clinical trials initiatives, and links to health promotion publications from various global organizations (https://sis.nlm.nih.gov/dimrc/zikavirus.html). The CDC provides a site dedicated to information on Zika virus; it focuses more on providing easily accessible educational materials as well as updates on outbreak surveillance tracking. In addition, there are free to download educational posters and brochures available, in both English and Spanish (https://www.cdc.gov/zika/index.html). The Pan American Health Organization also has a resource site focused on Zika education and prevention. The site offers similar information to the previous two but with a focus on global support and assistance (http://www.paho.org/hq/index.php?option=com_content&view=article&id=11585&Itemid=41688&lang=en).

Vaccine Type

Vaccine Name

Recommendation in Pregnancy

Considerations Unique to Pregnancy

Routine

Hepatitis A

Decision based on risk vs. benefit

Safety in pregnancy not determined. As this vaccine is manufactured from inactivated hepatitis A virus, the theoretical risk is low (Fiore, Wasley, & Bell, 2006).

Hepatitis B

Recommended in some circumstances

Pregnancy is not a contraindication to vaccination. Limited data suggest that developing fetuses are not at risk for adverse events when hepatitis B vaccine is administered to pregnant women. Available vaccines contain noninfectious hepatitis B virus surface antigen (HBsAg) and should cause no risk of infection to the fetus (Mast et al., 2006).

Pregnant women who are identified as being at risk for hepatitis B virus infection during pregnancy (e.g., having more than one sex partner during the previous 6 months, been evaluated or treated for a sexually transmitted disease, recent or current injection drug use, or having had an HBsAg-positive sex partner) should be vaccinated (Mast et al., 2005).

Human papillomavirus (HPV)

Not recommended

HPV vaccines are not recommended for use in pregnant women. If a woman is found to be pregnant after initiating the vaccination series, the remainder of the three-dose series should be delayed until completion of pregnancy. Pregnancy testing is not needed before vaccination. If a vaccine dose has been administered during pregnancy, no intervention is needed (Petrosky et al., 2015).

A new pregnancy registry has been established for 9vHPV. Pregnancy registries for 4vHPV and 2vHPV have been closed with concurrence from U.S. Food and Drug Administration (FDA) (Petrosky et al., 2015).

Influenza (inactivated) (IIV)

Recommended

Pregnant and postpartum women are at higher risk for severe illness and complications from influenza than women who are not pregnant because of changes in the immune system, heart, and lungs during pregnancy. Influenza vaccination can be administered at any time during pregnancy, before and during the influenza season. Women who are or will be pregnant during influenza season should receive IIV (Grohskopf et al., 2013).

Influenza (live attenuated influenza vaccine [LAIV])

Not recommended

LAIV is not recommended in pregnancy (Petrosky et al., 2015). The popular nasal spray form is LAIV.

Measles, mumps, rubella (MMR)

Contraindicated

MMR vaccines should not be administered to women known to be pregnant or attempting to become pregnant. Because of the theoretical risk to the fetus when the mother receives a live virus vaccine, women should be counseled to avoid becoming pregnant for 28 days after receipt of MMR vaccine. If the vaccine is inadvertently administered to a pregnant woman or a pregnancy occurs within 28 days of vaccination, she should be counseled about the theoretical risk to the fetus (McLean, Fiebelkorn, Temte, & Wallace, 2013).

Routine pregnancy testing of women of childbearing age before administering a live-virus vaccine is not recommended. MMR or varicella vaccination during pregnancy should not be considered a reason to terminate pregnancy (Kroger, Sumaya, Pickering, & Atkinson, 2011).

Rubella-susceptible women who are not vaccinated because they state they are or may be pregnant should be counseled about the potential risk for congenital rubella syndrome and the importance of being vaccinated as soon as they are no longer pregnant (Watson, Hadler, Dykewicz, Reef, & Phillips, 1998).

Meningococcal (MenACWY or MPSV4)

May be used if otherwise indicated

Pregnancy should not preclude vaccination with MenACWY or MPSV4, if indicated. Women of childbearing age who become aware that they were pregnant at the time of MenACWY vaccination should contact their health care provider or the vaccine manufacturer so that their experience might be captured in the vaccine manufacturer’s registry of vaccination during pregnancy (Cohn et al., 2013).

Meningococcal (B) (MenB)

Decision based on risk vs. benefit

No randomized controlled clinical trials have been conducted to evaluate use of MenB vaccines in pregnant or lactating women. Vaccination should be deferred in pregnant and lactating women unless the woman is at increased risk, and, after consultation with her health care provider, the benefits of vaccination are considered to outweigh the potential risks (MacNeil et al., 2015).

Pneumococcal conjugate (PCV13)

No recommendation found

Advisory Committee on Immunization Practices has not published pregnancy recommendations for PCV13 at this time.

Pneumococcal polysaccharide (PPSV23)

Inadequate data available for specific recommendation

The safety of pneumococcal polysaccharide vaccine during the 1st trimester of pregnancy has not been evaluated, although no adverse consequences have been reported among newborns whose mothers were inadvertently vaccinated during pregnancy (“Prevention of Pneumococcal Disease,” 1997).

Polio

May be used if needed

Although no adverse effects of inactivated polio vaccine (IPV) have been documented among pregnant women or their fetuses, vaccination of pregnant women should be avoided on theoretical grounds. However, if a pregnant woman is at increased risk for infection and requires immediate protection against polio, IPV can be administered in accordance with the recommended schedules for adults (Prevots, Burr, Sutter, & Murphy, 2000).

Tetanus and diphtheria (Td)

Should be used if otherwise indicated, but Tdap is preferred

Health care personnel should administer a dose of Tdap during each pregnancy irrespective of the patient’s prior history of receiving Tdap. To maximize the maternal antibody response and passive antibody transfer to the infant, optimal timing for Tdap administration is between 27 and 36 weeks of gestation, although Tdap may be given at any time during pregnancy (Centers for Disease Control and Prevention, 2013).

Currently available data suggest that vaccinating earlier in the 27- through 36-week period will maximize passive antibody transfer to the infant (Kim, Riley, Harriman, Hunter, & Bridges, 2017).

For women not previously vaccinated with Tdap, if Tdap is not administered during pregnancy, Tdap should be administered immediately postpartum (Centers for Disease Control and Prevention, 2013).

Available data from studies do not suggest any elevated frequency or unusual patterns of adverse events in pregnant women who received Tdap and that the few serious adverse events reported were unlikely to have been caused by the vaccine (Centers for Disease Control and Prevention, 2011).

Wound management: If a Td booster is indicated for a pregnant woman, health care providers should administer Tdap (Centers for Disease Control and Prevention, 2013).

Unknown or incomplete tetanus vaccination: To ensure protection against maternal and neonatal tetanus, pregnant women who never have been vaccinated against tetanus should receive three vaccinations containing tetanus and reduced diphtheria toxoids. The recommended schedule is 0, 4 weeks, and 6 through 12 months. Tdap should replace 1 dose of Td, preferably between 27 and 36 weeks gestation (Centers for Disease Control and Prevention, 2013).

Providers are encouraged to report administration of Tdap to a pregnant woman, regardless of trimester, to the appropriate manufacturer’s pregnancy registry: for Adacel to Sanofi Pasteur, telephone 1-800-822-2463 and for Boostrix to GlaxoSmithKline Biologicals, telephone 1-888-452-9622 (Murphy et al., 2008).

Tetanus, diphtheria, and pertussis (Tdap)

Recommended

See column information above for Td; remember Tdap is preferred and recommended for each pregnancy event.

Varicella

Contraindicated

Because the effects of the varicella virus on the fetus are unknown, pregnant women should not be vaccinated. Nonpregnant women who are vaccinated should avoid becoming pregnant for 1 month after each injection. For persons without evidence of immunity, having a pregnant household member is not a contraindication for vaccination (Marin, Güris, Chaves, Schmid, & Seward, 2007).

Wild-type varicella poses a low risk to the fetus. Because the virulence of the attenuated virus used in the vaccine is less than that of the wild-type virus, the risk to the fetus, if any, should be even lower (Marin et al., 2007).

Routine pregnancy testing of women of childbearing age before administering a live-virus vaccine is not recommended. If a pregnant woman is inadvertently vaccinated or becomes pregnant within 4 weeks after MMR or varicella vaccination, she should be counseled about the theoretical basis of concern for the fetus; however, MMR or varicella vaccination during pregnancy should not be considered a reason to terminate pregnancy (Kroger et al., 2011).

To monitor the pregnancy outcomes of women inadvertently vaccinated with varicella zoster virus (VZV)-containing vaccines immediately before or during pregnancy, Merck and Centers for Disease Control and Prevention (CDC) established the Merck/CDC Pregnancy Registry for VZV-Containing Vaccines in 1995. The low rate of exposure of varicella-susceptible women of childbearing age to VZV-containing vaccines, in addition to the rarity of the outcome, contribute to the low feasibility that the registry will provide more robust data on the risk for congenital varicella syndrome within a reasonable time frame. New patient enrollment was discontinued as of October 16, 2013. Merck will continue to monitor pregnancy outcomes after inadvertent exposures to VZV-containing vaccines during pregnancy or within 3 months before conception. CDC and the FDA will continue to monitor adverse events after vaccination with VZV-containing vaccines through the Vaccine Adverse Event Reporting System (VAERS). New cases of exposure immediately before or during pregnancy or other adverse events after vaccination with Varivax, ProQuad, or Zostavax should be reported to Merck (Telephone: 1-877-888-4231) and to VAERS (Marin et al., 2014).

Zoster

Contraindicated

Zoster vaccine (Zostavax) should not be administered to pregnant women. Additionally, Zostavax is not licensed for the age groups that include women of traditional childbearing ages (Harpaz, Ortega-Sanchez, & Seward, 2008).

In most circumstances, the decision to terminate a pregnancy should not be based on whether zoster vaccine was administered during pregnancy (Harpaz et al., 2008).

To monitor the pregnancy outcomes of women inadvertently vaccinated with VZV-containing vaccines immediately before or during pregnancy, Merck and CDC established the Merck/CDC Pregnancy Registry for VZV-Containing Vaccines in 1995. The low rate of exposure of varicella-susceptible women of childbearing age to VZV-containing vaccines, in addition to the rarity of the outcome, contributes to the low feasibility that the registry will provide more robust data on the risk for congenital varicella syndrome within a reasonable timeframe. New patient enrolment was discontinued as of October 16, 2013.

Merck will continue to monitor pregnancy outcomes after inadvertent exposures to VZV-containing vaccines during pregnancy or within 3 months before conception. CDC and the FDA will continue to monitor adverse events after vaccination with VZV-containing vaccines through the VAERS. New cases of exposure immediately before or during pregnancy or other adverse events after vaccination with Varivax, ProQuad, or Zostavax, should be reported to Merck (Telephone: 1-877-888-4231) and to VAERS (Marin et al., 2014).

Travel and other

Anthrax

Not recommended for low exposure risk but may be used with high risk exposure

In a pre-event setting, in which the risk for exposure to aerosolized Bacillus anthracis spores is presumably low, vaccination of pregnant women is not recommended and should be deferred until after pregnancy (Wright, Quinn, Shadomy, & Messonnier, 2010).

In a post-event setting that poses a high risk for exposure to aerosolized B. anthracis spores, pregnancy is neither a precaution nor a contraindication to postexposure prophylaxis. Pregnant women at risk for inhalation anthrax should receive anthrax vaccine adsorbed and 60 days of antimicrobial therapy as described (Wright et al., 2010).

Bacillus Calmette-Guerin (BCG) vaccine

Contraindicated

BCG vaccination should not be given during pregnancy. Even though no harmful effects of BCG vaccination on the fetus have been observed, further studies are needed to prove its safety (Centers for Disease Control and Prevention, 2016).

Japanese encephalitis (JE)

Inadequate data for specific recommendation

No controlled studies have assessed the safety, immunogenicity, or efficacy of Ixiaro in pregnant women. Preclinical studies of Ixiaro in pregnant rats did not show evidence of harm to the mother or fetus (Fischer, Lindsey, Staples, & Hills, 2010).

Rabies

May be used if otherwise indicated

Because of the potential consequences of inadequately managed rabies exposure, pregnancy is not considered a contraindication to postexposure prophylaxis. Certain studies have indicated no increased incidence of abortion, premature births, or fetal abnormalities associated with rabies vaccination. If the risk of exposure to rabies is substantial, pre-exposure prophylaxis also might be indicated during pregnancy. Rabies exposure or the diagnosis of rabies in the mother should not be regarded as reasons to terminate the pregnancy (Manning et al., 2008).

Typhoid

Inadequate data. Give Vi polysaccharide if needed.

No data have been reported on the use of either typhoid vaccine in pregnant women. In general, live vaccines like Ty21a are contraindicated in pregnancy. Vi polysaccharide vaccine should be given to pregnant women only if clearly needed (Jackson, Iqbal, & Mahon, 2015).

Vaccinia (smallpox)

Contraindicated in pre-exposure situations but recommended in postexposure.

Because of the limited risk but severe consequences of fetal infection, smallpox vaccine should not be administered in a pre-event setting to pregnant women or to women who are trying to become pregnant (Wharton et al., 2003).

If a pregnant woman is inadvertently vaccinated or if she becomes pregnant within 4 weeks after smallpox vaccination, she should be counseled regarding concern for the fetus. Smallpox vaccination during pregnancy should not ordinarily be a reason to terminate pregnancy. CDC has established a pregnancy registry to prospectively follow the outcome of such pregnancies and facilitate the investigation of any adverse pregnancy outcome among pregnant women who were inadvertently vaccinated. For enrollment in the registry, contact CDC at 404-639-8253 (Wharton et al., 2003).

Pregnant women who have had a definite exposure to smallpox virus (i.e., face-to-face, household, or close-proximity contact with a smallpox patient) and are, therefore, at high risk for contracting the disease, should be vaccinated. Smallpox infection among pregnant women has been reported to result in a more severe infection than among nonpregnant women. Therefore, the risks to the mother and fetus from experiencing clinical smallpox substantially outweigh any potential risks regarding vaccination. In addition, vaccinia virus has not been documented to be teratogenic, and the incidence of fetal vaccinia is low (Wharton et al., 2003).

When the level of exposure risk is undetermined, the decision to vaccinate should be made after assessment by the clinician and the patient of the potential risks vs. the benefits of smallpox vaccination (Rotz, Dotson, Damon, & Becher, 2001).

Yellow fever vaccine (YFV)

Decision based on risk vs. benefit

Pregnancy is a precaution for YFV administration, compared with most other live vaccines, which are contraindicated in pregnancy. If travel is unavoidable, and the risks for YFV exposure are felt to outweigh the vaccination risks, a pregnant woman should be vaccinated. If the risks for vaccination are felt to outweigh the risks for YFV exposure, pregnant women should be issued a medical waiver to fulfill health regulations (Staples, Gershman, & Fischer, 2010).

Because pregnancy might affect immunologic function, serologic testing to document an immune response to the vaccine should be considered (Staples et al., 2010).

Although no specific data are available, a woman should wait 4 weeks after receiving YFV before conceiving (Staples et al., 2010).

Adapted from the Advisory Committee on Immunization Practices Guidelines, available through the Centers for Disease Control and Prevention. Access at www.cdc.gov/vaccines/pregnancy/hcp/guidelines.html