What You Need to Know About the Zika Virus and Pregnancy

This article has been updated as of 8/12/2016

Open a newspaper or turn on the television and you will likely find an update on the world’s leading health crisis: Zika virus. When news broke in the United States earlier this year that a Zika virus epidemic was occurring in South and Central America, many were focused on the staggering number of babies being born with birth defects to mothers who had been infected with Zika during pregnancy. As of the beginning of February, the World Health Organization declared Zika virus a public health emergency of international concern. As the headquarters for MotherToBaby Illinois, a statewide teratogen service, Insight Medical Genetics is committed to providing the most up-to-date information on this crisis as it relates to the health and wellbeing of individuals who are planning a pregnancy, currently expecting, or who have recently delivered. Not very much is known about the effects of Zika virus on prenatal development, but we will continue to provide updates to this post with the most recent information as it becomes available. Read on to learn more about the Zika virus and how it might be pertinent to your health and that of current or future pregnancies.

What is Zika virus disease (Zika)?
Zika is a disease caused by the Zika virus.  Eighty percent of those who are affected with Zika will have no symptoms.  Of those who do have symptoms, they are usually mild, lasting a few days to a week.  The most common symptoms are fever, rash, joint pain, and conjunctivitis (red or pink eyes).  There is no specific treatment for Zika virus.

How is Zika virus spread?
Zika virus is usually spread to people through the bite of an infected mosquito.  However, we do not know exactly how often people who are bitten by an infected mosquito become infected themselves.  Zika virus can spread to different parts of the world when an uninfected mosquito bites an infected person.  When this happens, the mosquito can then become infected itself and has the potential to pass the virus onto another person that it bites. It is important to note that Zika virus can only be carried by certain types of mosquitoes.

 Zika virus can spread other ways as well. Zika virus CAN be passed from a pregnant woman to her developing baby. There are also some reports of Zika virus being transmitted through blood transfusion, semen, and vaginal fluids. The Centers for Disease Control and Prevention (CDC) has confirmed that Zika can be sexually transmitted, even if the infected person does not have symptoms at the time. In known cases of sexual transmission, the male partner had recently traveled to a region with active Zika transmission and was infected through a mosquito bite. However, current CDC recommendations include the possibility of sexual transmission from an infected woman.

Zika virus is NOT spread through other forms of physical contact, coughing, or sneezing.  There are currently no reports of infants getting Zika virus through breastfeeding.

How does Zika affect unborn babies?
In the spring of 2015 in Brazil, officials noticed a connection between the Zika virus outbreak and an increase in the number of babies born in the country with congenital microcephaly (a birth defect in which the size of a baby’s head is smaller than expected). Microcephaly can be a sign that the brain is not developing properly. In some cases microcephaly can cause developmental delays, including intellectual disability; growth problems; and other health problems like seizures. Since then, there have been reports of microcephaly (a small head and brain) in the babies of pregnant women who were infected with the Zika virus during pregnancy.

In April of 2016, the CDC announced that there was enough evidence to conclude that Zika virus infection during pregnancy is a cause of microcephaly and brain defects in developing babies.  Additionally, it has been linked to other issues including eye defects, hearing loss, and impaired growth. This does NOT mean that all pregnant women infected with the Zika virus will have babies with microcephaly or other birth defects. Research is still ongoing to better determine the link between Zika and these birth defects and other pregnancy problems.

Where is there active Zika virus transmission?
For an up-to-date map and list of infected countries and territories, click here.

The first report of active Zika transmission in the United States occurred in the Wynwood neighborhood of Miami, Florida. Zika may spread to other areas in the U.S., but this is the only report of active transmission in the United States at this time. For people who live in the Wynwood neighborhood or have traveled there any time after June 15, the CDC recommends the same guidelines as those for people who live in or traveled to other countries with active Zika transmission. These recommendations include that pregnant women should not travel to this area and pregnant women who live in or frequently travel to this area should be tested for Zika in the first and second trimester of pregnancy. In addition, residents of this area should talk to their healthcare provider for more information and should follow recommendations for preventing mosquito bites.

How long has the Zika virus been in the Americas? 
In May of 2015, an alert confirmed Zika virus infections in Brazil. Before this time, Zika virus outbreaks had occurred in Africa, Southeast Asia, and the Pacific Islands. It is thought that travelers coming to Brazil for a sporting event such as the 2014 World Cup may have brought the disease to South America. 

Local transmission of the Zika virus was first reported in Central America and Mexico in November 2015. It was first reported in the Caribbean in December 2015. Active transmission of Zika was first reported in the continental United States in July 2016.

I’m pregnant and have a trip planned to an area with active Zika virus transmission.  Should I postpone my trip?
The CDC recommends that women who are pregnant (in any trimester) do not travel to any area where Zika virus transmission is ongoing. If you must travel to one of these areas during pregnancy, you should talk to your healthcare provider. They will likely want to perform additional screening for you and your pregnancy when you return. You should also take precautions to avoid mosquito bites during your trip.

I’m pregnant and recently traveled to an area with active Zika virus transmission. What should I do?
You should talk to your healthcare provider, even if you are not sure whether or not you were bitten by mosquitoes or have symptoms of Zika. Your doctor may do a blood and/or urine test to check you for signs of infection. If you show signs of recent infection, she may perform an additional ultrasound during the pregnancy to measure the baby’s head and look at the baby’s brain.

If I am infected with Zika during pregnancy, how likely is it that my baby will have problems?
We don’t know. As of July 21, 2016, 433 U.S. women and 422 women in US Territories have been infected with the Zika virus during pregnancy.  Data regarding how many of these women have already given birth is not available. Of these, 13 babies have been born with Zika-associated birth defects. Six other pregnancies were also reported with evidence of Zika-associated birth defects but ended in miscarriage, stillbirth or due to termination of pregnancy. Some, but not all, of these birth defects were reported to be microcephaly. One CDC official has estimated that the risk of having a baby with birth defects due to the Zika virus is between 1 and 15%. More research is needed however, to better determine the risk.

Is it riskier to be exposed to Zika virus in the first trimester, the second trimester, or the third trimester?
We don’t know.  With many exposures, we know that the timing is important. Exposure during the first trimester of pregnancy, for example, may have a different effect than exposure during the third trimester. Preliminary evidence released in June 2016 has suggested that pregnant women who were infected with Zika during their third trimesters may not be at increased risk for babies with microcephaly. More data is needed however, to better determine what effect the timing of Zika virus infection has on the development of birth defects and other pregnancy problems.

I’d like to get pregnant in the near future, but I have a trip planned to an affected area.  How long should I wait after I return before I try to get pregnant?
The CDC currently recommends that men and women who have traveled to affected areas wait at least eight weeks after the exposure before trying to get pregnant. For men who experience Zika symptoms, the recommendation is to wait at least six months after symptoms start before trying to get pregnant. The time period is extended for infected males because we know that the Zika virus stays in semen longer than in other body fluids.

What precautions should I take if I plan to travel to a country with active Zika virus transmission?
There is currently no vaccine available to prevent Zika virus disease. The best prevention is to avoid mosquito bites. The Centers for Disease Control and Prevention recommends the following options to prevent mosquito bites:

  • Wear long-sleeved shirts and long pants.
  • Stay in places that have air conditioning or that use window and door screens to keep mosquitoes outside.
  • Sleep under a mosquito bed net if you are overseas or outside and are not able to protect yourself from mosquito bites.
  • Use Environmental Protection Agency (EPA)-registered insect repellents. All EPA-registered insect repellents are evaluated for effectiveness.
    • Always follow the product label instructions
    • Reapply insect repellent as directed.
    • Do not spray repellent on the skin under clothing.
    • If you are also using sunscreen, apply sunscreen before applying insect repellent.

Travelers should take steps to prevent mosquito bites for three weeks after returning from an area with Zika, even if they do not show symptoms, to prevent the spread of Zika through infected mosquitoes.

Is insect repellent safe to use in pregnancy?
The benefits of using insect repellent, including products containing DEET, outweigh any risks of the products themselves on the pregnancy.  For more information on insect repellents in pregnancy, see the MotherToBaby fact sheet.

Where can I get more information?
The Centers for Disease Control and Prevention (CDC) website contains the most up-to-date information on the Zika virus. 

You may also wish to contact MotherToBaby.  MotherToBaby, a service of the non-profit Organization of Teratology Information Specialists (OTIS), is suggested as a resource by many agencies including the CDC and the Food and Drug Administration’s (FDA) Office of Women’s Health. MotherToBaby offers evidence-based information about exposures, such as the Zika virus, during pregnancy and breastfeeding through its toll-free phone line (866-626-6847), text message (855-999-3525) and digitally via email and live chat on www.MotherToBaby.org. A fact sheet regarding Zika virus in pregnancy is also available on the MotherToBaby website. (http://mothertobaby.org/fact-sheets/zika-virus-pregnancy/).