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Division of Disease Control

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Pregnancy and Zika

Zika virus is particularly concerning for pregnant women due to the harmful effects the virus can have on her fetus.

  • The primary way that pregnant women become infected with Zika virus is through the bite of an infected mosquito.  
  • Zika virus can be spread through sex without a condom.
  • Zika virus can also be spread through blood transfusions and possibly via organ transplants.


Zika virus can be passed from a pregnant woman to her fetus during pregnancy or at delivery. To date, there are no reports of infants becoming infected with Zika virus through breastfeeding.

Zika and Microcephaly

Zika infection in pregnancy is linked to birth defects including microcephaly, which means that the fetus has a small head because of abnormal brain development, infants with small brain and/or skull), and other congenital abnormalities.

In addition to microcephaly, other birth defects have been detected in babies infected with Zika virus. These include curved joints, eye defects, hearing loss, and impaired growth. Not all babies born with congenital Zika infection will be born with all of these problems. Some babies may be healthy, but others who are born healthy at birth may later have slowed head growth resulting in microcephaly. Researchers are still collecting data to better understand how Zika infection affects babies.

For Pregnant Women

Pregnant women should:

We are still unsure when in pregnancy Zika infection might cause the most harm to the fetus, so pregnant women should avoid possible Zika exposure for the duration of their pregnancy.

For Women Trying to Become Pregnant

If a woman wishes to become pregnant and has recently traveled to an area with local Zika virus transmission, she should wait at least eight weeks before trying to become pregnant to be sure she does not infect her fetus. Men who are exposed to Zika virus can carry the virus in their semen. If your sex partner is male and has traveled to a country with local Zika transmission, you should postpone pregnancy and use condoms for six months after returning. This will help prevent your fetus from developing birth defects from Zika infection. Speak with your doctor or health care provider about your risk and birth control options in addition to condoms that will work best for you and your partner.

If families would like to speak to someone about a possible Zika virus infection or diagnosis during pregnancy and risk to the baby, please contact the Philadelphia Department of Public Health by calling at 215-685-6740 during business hours. 

For Men Who Have Pregnant Partners and Recently Traveled to Zika-Affected Areas

  • Zika can be spread by a man with Zika to his sex partners, even if the person does not have symptoms at the time. Zika can also remain longer in the semen of infected men and be spread through sex.  
  • Because Zika can cause certain birth defects, take steps to prevent your sex partner getting pregnant or from her getting Zika during pregnancy.
  • Use a condom every time you have sex during pregnancy OR don’t have sex during pregnancy.


CDC: Zika and Pregnancy

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