This sheet is about exposure to the Zika virus in pregnancy or while breastfeeding. This information is based on published research studies. 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 is pregnant and 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 if they do not have symptoms, they can still pass the virus to others through sex or to a fetus.
How can I protect myself 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 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, and 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 want to delay trying to get pregnant 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, look at the CDC website for any active Zika Travel Health Notices at: 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 CDC guidelines.
- 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 CDC guidelines.
- 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 CDC guidelines.
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 hard 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 CDC guidelines.
- 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 CDC guidelines.
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?
Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at research studies to try to understand if an exposure, like Zika, might increase the chance of birth defects in a pregnancy.
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 preterm delivery (birth before week 37), low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth), the fetus being smaller than expected for the timing in pregnancy (small for gestational age) and stillbirth.
Does having Zika virus in pregnancy affect future behavior or learning for the child?
Children with CZS have an increased chance of learning issues.
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?
People who have Zika symptoms and might have been exposed to Zika virus from travel or sex with someone who has recently traveled should be tested. The CDC has more information about testing here: https://www.cdc.gov/zika/testing/index.html.
What screenings or tests are available to see if my pregnancy has birth defects or other issues?
Prenatal ultrasounds can be used to screen for some birth defects, such as microcephaly. Ultrasound can also be used to monitor the growth of the pregnancy. Talk with your healthcare provider about any prenatal screenings or testing that are available to you. There are no tests available during pregnancy that can tell how much effect there could be on future behavior or learning.
Breastfeeding while I have Zika virus:
Zika virus has been found in breast milk. 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 man has Zika virus, can 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). This can affect men’s fertility (ability to get a partner pregnant). Sperms count returned to normal within several months after the infection cleared.
If a man 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. Men 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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