This sheet is about exposure to the Zika virus in pregnancy and while breastfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.
What is Zika? How do people get it?
Zika is a virus that is usually spread by infected mosquitoes. Not all mosquitoes carry the Zika virus, and not every person bitten by an infected mosquito will get Zika. Other ways people can get Zika include sexual contact with an infected partner (vaginal, anal, or oral sex, or sharing of sex toys), and through blood to blood contact with infected blood (from transfusions, needle sticks, or sharing needles with an infected person). A person who has Zika can also pass the infection to their fetus during pregnancy.
Four out of 5 people who have Zika virus do not have symptoms. Those who do have symptoms usually have a mild flu-like illness with fever, rash, headache, joint and/or muscle pain, and conjunctivitis (“pink eye”). Symptoms can begin 3-7 days after being infected and can last for several days to a week. The symptoms of Zika can be treated, but there is no cure or vaccine for Zika. Even if an infected person treats their symptoms, or even if they do not have symptoms, they can still pass the virus to others through sex or to a developing fetus.
How can I protect my pregnancy from Zika virus during travel?
Prevent mosquito bites during and after travel by using insect repellent and taking other steps recommended by the Centers for Disease Control and Prevention (CDC) at https://www.cdc.gov/mosquitoes/prevention/preventing-mosquito-bites-while-traveling.html. MotherToBaby has fact sheets for Insect Repellents at https://mothertobaby.org/fact-sheets/insect-repellents/ and DEET at https://mothertobaby.org/fact-sheets/deet-nn-ethyl-m-toluamide-pregnancy/.
Depending on where you travel, it might be recommended to take or consider taking steps to prevent sexual transmission of Zika (getting or passing the virus through sex) and/or delaying pregnancy after travel. To prevent sexual transmission of Zika, use condoms or dental dams, do not share sex toys, or do not have sex during travel and for a period of time after travel (2 months for biological females or 3 months for biological males). Follow these same timeframes if you are delaying conceiving a pregnancy after travel (2 months for biological females and 3 months for biological males). See below for specific recommendations based on Zika risk at your destination(s).
Check for Zika risk at your destination(s). Before traveling, consult the CDC website for any active Zika Travel Health Notices: https://wwwnc.cdc.gov/travel/notices.
- If you are pregnant, avoid traveling to areas with active Zika Travel Health Notices. If you must travel, prevent mosquito bites and sexual transmission of Zika virus during and after travel according to the guidelines above.
- If your partner is pregnant and you choose to travel to an area with an active Zika Travel Health Notice, prevent mosquito bites and sexual transmission during and after travel according to the guidelines above.
- If you or your partner are planning a pregnancy and you travel to an area with an active Zika Travel Health Notice, prevent mosquito bites, prevent sexual transmission, and delay pregnancy according to the guidelines above.
Some areas still have low levels of Zika virus transmission even if there is no active Zika Travel Health Notice. For information about Zika risk in specific countries and territories, see https://www.cdc.gov/zika/geo/index.html. It is difficult to know the exact level of transmission in many areas. Carefully consider the risks of Zika before traveling to areas with current or past transmission of Zika virus.
- If you or your partner are pregnant and you travel to an area with current or past transmission, prevent mosquito bites during and after travel. If you are concerned about the risks of Zika, prevent sexual transmission during and after travel according to the guidelines above.
- If you or your partner are planning a pregnancy and you travel to an area with current or past transmission, prevent mosquito bites during and after travel. If you are concerned about the risks of Zika, prevent sexual transmission during and after travel, and consider delaying pregnancy according to the guidelines above.
Does having Zika virus increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Zika infection in pregnancy can increase the chance of miscarriage.
Does having Zika virus in pregnancy increase the chance of birth defects?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. When a person who is pregnant gets Zika, the virus can pass to the fetus. If this happens, the fetus has an increased chance of certain birth defects and developmental problems known as congenital Zika syndrome (CZS). CZS can include microcephaly (very small head and brain), severe brain defects, eye defects, hearing loss, and/or problems with the development and movement of the joints and limbs.
Studies suggest that about 5-10% of babies born to people with confirmed Zika infection during pregnancy will have birth defects related to the infection. The chance is highest with a Zika infection in the first trimester, but birth defects related to Zika can also happen after infection in the second or third trimester.
Does having Zika virus increase the chance of other pregnancy-related problems?
Zika infection in pregnancy can increase the chance of stillbirth, preterm delivery (birth before week 37), the fetus being smaller than expected for the timing in pregnancy (small for gestational age) and having low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).
Does having Zika virus in pregnancy affect future behavior or learning for the child?
Sometimes a baby can be born with no apparent effects from Zika infection, but can later have slowed head and brain growth (called postnatal microcephaly). Research has also shown that even when a baby does not have noticeable Zika-associated issues, there is still a chance they can later have issues, such as delays in meeting developmental milestones, or epilepsy (seizure disorder).
Can I be tested for Zika?
Zika testing is not a good way to know if it is safe to get pregnant or if you could pass the virus to your partner through sex. There is no available test to know if there is Zika virus in a person’s semen. People who are experiencing Zika symptoms and have had possible exposure to Zika virus from travel or sex with someone who has recently traveled should be tested. CDC has more information about testing here: https://www.cdc.gov/zika/testing/index.html.
Breastfeeding and Zika virus:
Zika virus has been found in breast milk, but there have not been any reported cases of infants getting Zika through breastfeeding. Experts believe that the benefits of breastfeeding outweigh any potential risks of Zika virus infection through breastfeeding.
Some research suggests that children with congenital Zika syndrome (CZS) can have trouble with feeding, such as issues with swallowing or suckling. If you are concerned about your baby’s feeding habits or weight gain, talk with your baby’s pediatrician. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a male has Zika virus, could it affect fertility or increase the chance of birth defects?
A study showed that having a Zika infection lowered sperm count (number of sperms produced), but sperm count returned to normal within several months after infection. Lower sperm count can affect fertility (ability to get partner pregnant).
If a male has Zika he can pass the virus to his partner through unprotected sex. This can increase the chance of birth defects in his partner’s pregnancy. Males who might have been exposed to Zika virus should take steps to avoid passing the virus to a partner through sex, even if they do not have symptoms (for more information, see https://www.cdc.gov/zika/prevention/index.html). For more general information on paternal exposures, please see the MotherToBaby fact sheet at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
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OTIS/MotherToBaby encourages inclusive and person-centered language. While our name still contains a reference to mothers, we are updating our resources with more inclusive terms. Use of the term mother or maternal refers to a person who is pregnant. Use of the term father or paternal refers to a person who contributes sperm.
