Vaccinations before, during and after pregnancy.

Prenatal screening

Women who are planning to become pregnant should make sure that they are up to date on their immunizations. This will protect them and the unborn child from many diseases.

The measles, mumps, rubella, and chickenpox (varicella) vaccines are particularly important for women of childbearing age, as these cannot be given when pregnant. If a woman is infected with any of this in pregnancy, particularly first trimester, it results in adverse pregnancy outcome. 

Patients should check with their physician, who can request a blood test to see the blood levels of antibodies against these viruses, because of prior vaccination or prior history of disease itself.

MMR- If you need to get the vaccine for Rubella, avoid getting pregnant for at least a month after receiving the MMR.

Varicella- Similarly, if you are not immune to chickenpox, get vaccinated at least a month before getting pregnant.

HPV Vaccine- The human papillomavirus (HPV) vaccine is recommended for nonpregnant girls and women 9 to 26 years of age. It is contraindicated during pregnancy, although evidence suggests it is safe if pregnant women receive it inadvertently.

Hepatitis B- A woman should get tested for anti-HBs before she is pregnant to see whether the vaccine was well taken and she is immune to infection.

Vaccines during pregnancy

The tetanus, diphtheria, acellular pertussis (Tdap) vaccine is recommended for every pregnant woman during each pregnancy. It should be given as early as possible between 27 and 36 weeks of gestation, to facilitate the passive transfer of maternal antibodies. Infants exposed in utero to Tdap vaccine were better protected against pertussis during the first year of life than infants not exposed in utero.

Influenza (flu)- Every pregnant woman who is pregnant around the influenza season should be vaccinated against the seasonal flu as she is at high risk for developing flu complications. The vaccine has no adverse effect on fetus, on the contrary the unborn baby is protected against flu for first 6 months of life, till the baby is eligible to receive the vaccine.

The nasal spray influenza vaccine is contraindicated as it is made of live virus.

Vaccines for special circumstances

Hepatitis A- Pregnant woman who is at risk for developing Hepatitis A should receive the vaccine as the virus can be passed on to fetus.

Hepatitis B- It is only recommended for pregnant women who are at high risk for developing the infection like unimmunized women who live with someone infected with hepatitis B and for completing the series if started before becoming pregnant.

Poliomyelitis- Although polio has been eradicated from most developed and some developing countries, polio vaccine is usually not given in pregnancy unless travel to an area where polio is prevalent is unavoidable. In such circumstances, she may receive the inactivated polio vaccine (IPV). 

Pneumococcus- Ideally the vaccine is given before pregnancy, but  if woman is at high risk for pneumococcal infection, the vaccine appears to be safe if given in second and third trimester.

Varicella- Because the effects of the varicella virus on the fetus are unknown, it is contraindicated in pregnant women.

Vaccines for travel

Yellow fever- May be given if benefit outweigh risk. 

BCG- contraindicated

Typhoid- Inadequate data to make any recommendations

Rabies – Pregnancy is not considered a contraindication for post-exposure prophylaxis. If risk of exposure is substantially high, pre-exposure prophylaxis could be considered.

Passive Immunization during pregnancy

No known risk exists for the fetus from passive immunization of pregnant women with immune globulin preparations.

Prenatal screening

Every Pregnant woman should be tested for immunity to rubella and varicella and be tested for the presence of HBsAg during every pregnancy. Women who are found susceptible to rubella and varicella should be vaccinated immediately after delivery.

If a woman is found to be HBsAg positive, the infant should receive HBIG and begins the hepatitis B vaccine series no later than 12 hours after birth.

Breastfeeding and vaccines.

Inactivated and live-virus vaccines are not contraindicated in pregnant woman, although the virus can replicate in mother, it is not excreted in human milk.

Small pox and yellow fever vaccines are contraindicated in lactating mother, although if travel to an area where Yellow fever is endemic is imminent, it can be given. 

Source: CDC Guidelines for Vaccinating Pregnant Women

Society for Maternal-Fetal Medicine (SMFM) recommendations for screening, treatment, and prevention of vertical transmission of Hepatitis B in pregnancy

The Primary source of this article is the recommendation published by Society for Maternal-Fetal Medicine (SMFM) for screening, treatment and prevention of vertical transmission of Hepatitis B in the January issue of American Journal of Obstetrics and Gynecology by Dionne-Odom J. et al.

DOI: http://dx.doi.org/10.1016/j.ajog.2015.09.100

Nearly 240 million people worldwide are infected with hepatitis B virus (HBV).

Specific to pregnancy, an estimated prevalence of 0.7-0.9% for chronic hepatitis B infection among pregnant women in the United States has been reported, with >25,000 infants at risk for chronic infection born annually to these women.

While transmission through sexual intercourse and intravenous drug abuse are the major risk factors for acquisition of hepatitis B among adults in the United States, perinatal transmission is responsible for up to 50% of HBV infection worldwide

Vertical transmission of HBV from infected mothers to their fetuses or newborns, either in utero or peripartum, remains a major source of perpetuating the reservoir of chronically infected individuals globally.

From a global public health perspective, chronic HBV infection is the major source of hepatocellular carcinoma, leading to 50% of cases worldwide and 80% in high-endemic areas for HBV.

In contrast to HBV acquisition in adulthood, which more commonly leads to acute resolved infection and immunity, perinatal/neonatal HBV is more likely to lead to chronic infection and its long-term disease risks. Chronic hepatitis B infection will develop in up to 90% of exposed neonates who do not receive appropriate immunoprophylaxis, in contrast to 10-25% of infected children and only 5-10% of exposed immunocompetent adults.

Identification of pregnant women with chronic HBV infection through universal screening has had a major impact in decreasing the risk of neonatal infection. Recent data demonstrate that 95% of pregnant women are currently screened prior to delivery for evidence of chronic HBV infection, with rates of perinatal transmission decreasing significantly over the past 2 decades.

The recommendation of Society for Maternal-Fetal Medicine (SMFM) for screening, treatment and prevention of vertical transmission are:

(1) Perform routine screening during pregnancy for HBV infection with maternal HBsAg testing (grade 1A).

(2) Administer hepatitis B vaccine and HBV immunoglobulin within 12 hours of birth to all newborns of HBsAg-positive mothers or those with unknown or undocumented HBsAg status, regardless of whether maternal antiviral therapy has been given during the pregnancy (grade 1A).

(3) In pregnant women with HBV infection, suggest HBV viral load testing in the third trimester (grade 2B).

(4) In pregnant women with HBV infection and viral load >6-8 log 10 copies/mL, HBV-targeted maternal antiviral therapy should be considered for the purpose of decreasing the risk of intrauterine fetal infection (grade 2B).

(5) In pregnant women with HBV infection who are candidates for maternal antiviral therapy, tenofovir should be used as a first-line agent (grade 2B).

 (6) It is  recommend that women with HBV infection be encouraged to breast-feed as long as the infant receives immunoprophylaxis at birth (HBV vaccination and hepatitis B immunoglobulin) (grade 1C).

 (7) HBV infected women who have an indication for genetic testing, invasive testing (eg amniocentesis or chorionic villus sampling) may be offered–counseling should include the fact that the risk for maternal-fetal transmission may increase with HBV viral load >7 log 10 IU/mL (grade 2C).

(8) Cesarean delivery should not be performed for the sole indication for reduction of vertical HBV transmission (grade 2C).

Issues to be considered in a pregnant woman diagnosed as a chronic HBV carrier?

The majority of pregnant women diagnosed with chronic HBV infection will be asymptomatic and identified through routine screening with initial prenatal laboratory tests.

Identification of a pregnant woman as chronically HBV infected also presents an important opportunity to counsel her regarding risks to other family and household members. HBV is most easily transmitted via sexual exposure or blood exposure but can also be transmitted through casual shared use of household items such as eating utensils and toothbrushes, as well as through personal contact such as kissing or routine childcare. Therefore, family and household members should be evaluated for HBV status and referred for vaccination if found to be uninfected and nonimmune.

The pregnant woman herself should also be assessed for immunity status for hepatitis A and offered vaccination if not immune, since coinfection with another viral hepatitis results in compounded morbidity.

To aid in counseling regarding risks and potential management options as outlined above, baseline LFTs should also be drawn when a positive HBsAg test result is obtained, along with a baseline quantitative HBV-DNA level.

The woman should also be counseled regarding exposures to potentially hepatotoxic medications, even those available over the counter, such as acetaminophen, and to avoid the use of alcohol even when not pregnant.

Even if the maternal viral load is low and antiviral therapy during pregnancy is not recommended, the newborn should still receive standard prophylaxis with HBIG and HBV vaccine within 12 hours of birth, and ongoing surveillance of the woman’s hepatic function after pregnancy is indicated.

References:

Hepatitis B in pregnancy screening, treatment, and prevention of vertical transmission.Dionne-Odom, Jodie et al. American Journal of Obstetrics & Gynecology, Volume 214, Issue 1, 6 - 14