Protect Yourself: Zika Virus Could Increase Birth Defects 20-Fold

Traveling, family planning, or pregnant? Use bug spray and condoms

Pregnant woman drinking tea outside

If you live in most areas of the continental United States, the chances of being infected with the Zika virus are pretty low. However, in Florida in 2016, there were 262 cases of locally acquired Zika infection—something to keep in mind if you're headed south for spring break or going on vacation and thinking of starting a family.

This statistic means that 262 people caught Zika while in Florida and not from traveling to other countries in the Caribbean, Central America, and South America—which are in the throes of an outbreak and where the virus is much more prevalent.

Furthermore in Florida in 2016, 224 pregnant women were diagnosed with the Zika virus.

It's been widely reported that infection with the Zika virus during pregnancy is linked to severe birth defects. More specifically, Zika can cause brain abnormalities in the newborns. A new study published by the CDC estimates that women with Zika virus are 20 times more likely to give birth to a baby with birth defects. We are beginning to quantify the effects of Zika.

Zika Symptoms

About 80 percent of people who are infected with Zika experience no symptoms. In those who do develop symptoms, Zika is a mild febrile (fever) illness. However, pregnant women who are infected with the Zika virus can have babies with microcephaly, or small heads, and other brain defects as well as eye problems. However, the full ambit of such birth defects is unknown. Therefore, pregnant women should avoid infection with the Zika virus at all costs.

Pregnant women can be infected with the Zika virus during any trimester. The data on Zika virus infection in women are limited. Of note, there’s no evidence that pregnant women are more susceptible to the Zika virus or experience symptoms that are worse than those experienced by those people who are not pregnant.

In other words, Zika may very well present the same in pregnant women as others, yet cause severe birth defects in unborn children.

Prevalence of Zika-Related Birth Defects

Publishing in the Morbidity and Mortality Weekly Report (MMWR) in March 2017, researchers were able to estimate how much more likely a woman infected with Zika is to give birth to a baby with birth defects.

The researchers first used pre-Zika data to retrospectively establish a baseline for birth defects similar to those seen in babies born to mothers infected with the Zika virus. Specifically, the researchers analyzed the prevalence of birth defects in Massachusetts, North Carolina, and Atlanta, Georgia, between 2013 and 2014. Of note, these areas were chosen because they collect robust and detailed information on all types of birth defects, which predated the Zika outbreak.

Then, the researchers assessed the proportion of babies born to infected mothers between January 15 and September 22, 2016, using the U.S. Pregnancy Zika Registry.

Comparing pre-Zika and post-Zika data, the researchers suggest that the chances that an infected mother will give birth to a child with birth defects is about 20 times more.

Granted, comparing state data with CDC data isn't a perfect comparison.

However, the comparison still gives us a good idea of the magnitude of risk. This study also underscores the importance of using birth registries to tally birth defects in this new age of Zika.

According to the researchers:

These data demonstrate the critical contribution of population-based birth defects surveillance to understanding the impact of Zika virus infection during pregnancy. In 2016, CDC provided funding for 45 local, state, and territorial health departments to conduct rapid population-based surveillance for defects potentially related to Zika virus infection, which will provide essential data to monitor the impact of Zika virus infection in the United States.

Infection From Mosquitoes

The Zika virus is spread by Aedes mosquitoes, which bite during the day and the night. As of yet, there is no vaccine for Zika. And if you’re pregnant or thinking about becoming pregnant, you should be very careful to avoid infection.

If you’re pregnant and live in an area where Zika is transmitted locally or end up traveling to such areas while pregnant, it’s super important to avoid getting bit by a mosquito. Here are some tips to keep in mind:

  • Bug repellents decrease the risk that you’ll get bit. The Environmental Protection Agency (EPA) hosts a search tool that determines which bug repellent is right for you. And the CDC recommends that to protect yourself from Zika, it’s best to use EPA-registered repellents. (EPA-registered repellents have been tested for effectiveness.) When using bug repellent, closely follow directions on the packaging and reapply as necessary. Furthermore, if you’re also using sunscreen, apply the sunscreen before the bug repellent.
  • You can also prevent getting bit by mosquitoes by removing all standing water from your living area. Aedes aegypti, the type of mosquito that primarily spreads the Zika virus, loves to breed in man-made containers close to or containing water, like vases, trash cans, pet bowls, buckets, flowerpots, and tires. These mosquitoes lay their eggs on the side of these containers and the eggs stick to them like glue. In order to get rid of the eggs, they need to be scrubbed off. Moreover, these eggs can survive for up to eight months when dried out. When water eventually does cover the eggs, the eggs hatch and become adults in about a week. If you must store water in bottles or other containers for later consumption or use, make sure that these containers are sealed well. 

Most importantly, if you don’t live in an area where the Zika virus is spread—in other words, most of the United States—you should avoid traveling to areas where Zika is spread if you're pregnant or thinking about pregnancy. These areas include Mexico, The Bahamas, The Dominican Republic, Brazil, Fiji, American Samoa, and many more. The CDC offers a full map of all the countries where Zika is transmitted locally.

Please keep in mind that the Zika virus has also been found to be transmitted in a few areas that are part the United States, too. Specifically, pregnant women should avoid travel to the U.S. Virgin Islands, Puerto Rico, Miami, and Brownsville, Texas.

Infection From Sex

​The Zika virus can also be transmitted through vaginal, anal, and oral sex. It can also be spread using sex toys. Condoms can reduce the chance of being infected. Please note that the Zika virus can be passed from one person to another before the development of symptoms, during illness, and even after the symptoms pass.

Furthermore, Zika can also be passed from a person who is infected but doesn’t have symptoms. The CDC recommends that for those at risk of being infected with the Zika virus, condoms be used properly—from start to finish—during every incidence of vaginal, anal, or oral sex. Alternatively, pregnant women can abstain from having sex during their entire pregnancy.

Planning Pregnancy

For women who have traveled to an area where Zika is spread or have had sex without a condom with a person who has been infected with the Zika virus, it’s important to wait at least eight weeks before becoming pregnant. Symptoms of the Zika virus can last from several days to a week.

For those women who are infected with the Zika virus, it’s important to wait at least eight weeks after symptoms start before becoming pregnant. Men should wait at least six months after infection or last possible exposure before impregnating a woman for fear of transferring the virus.

A Word From Verywell

If you and your partner live in an area where the Zika virus is transmitted and plan on becoming pregnant, please discuss your options with your physician. Ultimately, decisions about becoming pregnant in an area where Zika is transmitted are complex and personal.

Furthermore, circumstances vary from couple to couple, which is why counseling is key. A trusted physician or health care provider can help guide you through the decision-making process. If you live in an area where Zika is being actively transmitted, you may want to delay getting pregnant.


Cragen, JD, et al. Baseline Prevalence of Birth Defects Associated with Congenital Zika Virus Infection — Massachusetts, North Carolina, and Atlanta, Georgia, 2013–2014. Morbidity and Mortality Weekly Report. 2017; 66(8): 219–222.

DynaMed Editorial Team. Zika virus in pregnancy and congenital Zika syndrome. Last updated 2017 January 30. Available from DynaMed:

Interim Guidelines for Pregnant Women During a Zika Virus Outbreak — United States, 2016. Weekly. January 22, 2016; 65(2):30–33.

Zika, Mosquitoes, and Standing Water. Public Health Matters Blog. March 22, 2016.

Zika virus. Disease and Conditions.