Questions and Answers About Smallpox Vaccination while Pregnant or Breastfeeding

If a woman wants to get pregnant, how long does she need to wait after receiving the smallpox vaccine?

A woman should wait until the vaccine site has completely healed and the scab has fallen off before trying to become pregnant after vaccination. Generally, this means women who have received the smallpox vaccine should wait at least four weeks (28 days) before becoming pregnant. Until that time, effective measures should be taken to prevent pregnancy, such as birth control pills, injections, implants, IUDs, or abstinence. Other methods of birth control, such as condoms, diaphragms, spermicide, and natural family planning are less effective.

If a woman wants to get pregnant, how long does she need to wait if a close contact has received the smallpox vaccine?

A close contact includes anyone living in your household and anyone with whom you have close, physical contact (such as a sex partner). A woman should wait until the vaccine site in her close contact has completely healed and the scab has fallen off before trying to become pregnant after vaccination. Generally, this means a woman should wait at least four weeks (28 days) after close contact with a vaccinated person before becoming pregnant. Until that time, effective measures should be taken to prevent pregnancy, such as birth control pills, injections, implants, IUDs, or abstinence. Other methods of birth control, such as condoms, diaphragms, spermicide, and natural family planning are less effective.

Should a woman of child-bearing age get a pregnancy test before receiving a smallpox vaccine?

Any woman who thinks she could be pregnant should perform a pregnancy test, by using her first morning urine, on the day vaccination is scheduled. However, even the most sensitive tests may not be able to detect early pregnancies (those less than two weeks along). Thus, if a woman thinks she might be pregnant, she should not get the smallpox vaccine.

Is it safe for pregnant women to have contact with a person who has recently received the smallpox vaccine?

Women who are pregnant should not have close contact with anyone who has recently (within the last 28 days) received the smallpox vaccine. A close contact includes anyone living in your household and anyone with whom you have close, physical contact (such as a sex partner or someone you share a bed with). Other friends or people you work with are not considered close contacts.

Is smallpox vaccination or close contact with a recently vaccinated person during pregnancy a reason to consider pregnancy termination?

There have been less than 50 cases of fetal vaccinia ever reported in the world. Because fetal vaccinia is so rare, smallpox vaccination during pregnancy should not be a reason to consider termination of pregnancy.

Is it safe for a woman to breastfeed her baby if a close contact received the smallpox vaccine?

Yes. However, anyone who receives the smallpox vaccine should remember to wash their hands with soap and warm water after direct contact with the vaccination site, or anything that has touched the vaccination site (bandages, clothing, towels, bedding, etc.). This is will help prevent the spread of vaccinia virus to contacts, including young babies. If a breastfeeding mother who has had close contact with a person recently vaccinated against smallpox develops a rash, she should check with her healthcare provider to determine if the rash is related to the smallpox vaccine. If she has a vaccine-related rash, breastfeeding should not take place until all scabs from the rash have fallen off. A woman who desires to maintain her milk supply may continue to pump breast milk, but the milk should be discarded until her scabs fully separate.

What if my obstetrician has been vaccinated?

The close contact required for transmission of vaccinia infection to close contacts is not likely to occur in the healthcare setting. Healthcare workers who have received smallpox vaccine are taking precautions to practice strict vaccination site care and hand hygiene, so that their patients will not come into contact with the vaccination site, or with any materials that have come into contact with the vaccination site.

Is it safe for women who received smallpox vaccine during pregnancy to breastfeed their babies?

Pregnant women should not receive the smallpox vaccine unless they have been exposed to smallpox. If a pregnant woman is vaccinated, she is likely to have been in the very early stages of her pregnancy at the time of vaccination. Her scab will separate from the vaccination site in about three weeks after vaccination, and by the time she delivers her baby, it will be safe for her to breastfeed. Breastfeeding should not take place until the vaccination scab has separated from the vaccination site.

If pregnant women are vaccinated with the smallpox vaccine are there any special risks to the fetus?

Smallpox vaccine has not been shown to cause an increased risk of serious birth defects. Except for the rare case of fetal vaccinia, smallpox vaccination of pregnant women has not been linked with prematurity, low birth weight, or other serious birth problems. Babies born without fetal vaccinia are not known to have a greater risk of future medical problems Fetal vaccinia is an infection in the unborn baby that can lead to premature delivery, skin rash with scarring, stillbirth, or death of the baby after delivery. Sometimes a baby who develops fetal vaccinia is born with skin scars but is otherwise healthy. Fewer than 50 cases of fetal vaccinia have ever been reported in the world, and only three of these cases were reported in the United States. When smallpox vaccine was routinely given in the United States from 1967 to 1971, only one case of fetal vaccinia occurred among an estimated 90,000 to 280,000 pregnant women who received the vaccine. It is estimated that 5,700 to 17,000 of these pregnant women were receiving the vaccine for the first time. Therefore, although the risk to the unborn baby is known to exist, that risk is low and fetal vaccinia is very rare.

Are there special considerations at the time of delivery for women exposed to smallpox vaccine during pregnancy?

Most women who receive smallpox vaccine during pregnancy will deliver normal babies, and standard delivery procedures should be followed. All pregnant women who have received the smallpox vaccine during pregnancy should let their healthcare provider and their baby’s healthcare provider know about their vaccination.

Should pregnant women who receive the smallpox vaccine undergo any special medical tests? 

There is no known test that can reliably confirm before birth if a baby is infected with vaccinia. Pregnant women who have received the smallpox vaccine should receive regular prenatal care, and should discuss their smallpox vaccination with their healthcare provider. There are tests that are being studied in a research setting to confirm infection after birth, and these might prove helpful in the future. These tests involve taking a sample of blood from the umbilical cord after the baby is born and testing for the presence of vaccinia virus or antibodies (substances that help fight off infection) against the virus. Likewise, if a pregnancy ends in miscarriage or termination the tissue from the fetus may be tested for the smallpox vaccine virus.

If a pregnant woman who has received smallpox vaccine develops a serious reaction what should she do?

Anyone who thinks they are having a serious reaction to the smallpox vaccine should either call the phone number provided on the "Post-Vaccination and Follow-Up Information Sheet" given to them at the time of vaccination, call their healthcare provider, or visit an emergency room.

Should pregnant women who have received the smallpox vaccine receive Vaccinia Immune Globulin (VIG)?

Vaccinia Immune Globulin (VIG) is a treatment that can be used to help people who have certain serious reactions to smallpox vaccine. VIG is made from the blood of people who have gotten the smallpox vaccine more than once. It contains substances (antibodies) that give protection from vaccinia infection. Women should contact their healthcare provider regarding use of VIG. Currently, CDC’s Advisory Committee on Immunization Practices does not recommend preventive use of Vaccinia Immune Globulin (VIG) for pregnant women. However, if a woman has another complication from smallpox vaccine that could be treated with VIG, it is ok for her to receive it while she is pregnant.

How do I sign up for the Registry if I have received the smallpox vaccine?

Pregnant women who have received the smallpox vaccine, or pregnant women whose close contacts have received the smallpox vaccine, may contact their healthcare provider or their state health department for help in enrolling in the registry. The Pregnancy Registry is now being managed by the military for both military and civilian sectors. Health-care providers and staff from state health departments are encouraged to report all exposed pregnant women to the registry by completing and returning the enrollment form: http://www.vaccines.mil/documents/1103SmallpoxVax_Pregnancy%20VAERS.pdf

• Page last reviewed: March 13, 2009
• Page last updated: March 13, 2009
• Content source: Division of Bioterrorism Preparedness and Response (DBPR), National Center for Preparedness, Detection, and Control of Infectious Diseases (NCPDCID), Coordinating Center for Infectious Diseases (CCID)