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Mental & physical health

Pregnancy risks

Zika virus is particularly concerning for pregnant women due to the harmful effects the virus can have on a 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 all types of sex (vaginal, anal, and oral).
  • Zika virus can be spread through blood transfusions and possibly via organ transplants.

A pregnant woman can pass Zika virus to her fetus. This can happen during pregnancy or at delivery. To date, there are no reports of infants getting Zika virus through breastfeeding.

Microcephaly and other birth outcomes

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, and infants have a small brain and/or skull and other congenital abnormalities.

Other birth defects have also 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 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 impacts babies.

For pregnant women

Pregnant women should:

  • Avoid travel to a country or region with Zika transmission.
  • Avoid unprotected sex if your partner (regardless of gender) traveled to a country with Zika.
  • Use condoms or abstain from sex until the baby is born.

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

For women trying to become pregnant

If you wish to become pregnant and have recently traveled to an area with local Zika virus transmission, you should wait at least eight weeks before trying to become pregnant to be sure you do not infect your 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 you 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 he does not have symptoms at the time. Zika can remain 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.