What Pregnant Women Need to Know About Zika Virus

How to stay informed and calm in the face of an uncertain health risk

by Amanda MacMillan
February 9, 2016

For many women, pregnancy is an extremely emotional time under the best circumstances. It's normal to want to do everything you can to have a healthy baby and to be concerned about anything that might threaten your chances of this. So of course you may feel anxious when news breaks that a rapidly spreading mosquito-borne virus – one that's potentially linked to miscarriages and birth defects – is inching closer to the United States.

As you stay informed about Zika, it's important to evaluate the risks of the disease in context to get an idea of whether it's a realistic threat to you and your baby. Here's everything we know so far and what you can do to stay safe. 

Constantly changing news
The number of countries where Zika is spreading continues to grow. Scientists' understanding of the Zika virus, including how it's transmitted, its association with birth defects, and what we can do about it, is also in constant flux.

As yet, there is no definitive link between the mosquito-borne virus and microcephaly, a birth defect that causes an abnormally small head as well as other mental and neurological problems in babies. That said, most medical experts do agree that some connection between the Zika virus and microcephaly (also an increased risk of miscarriage) seems likely.

However, the early reports that more than 4,000 cases of microcephaly had been reported in Brazil since October have now been challenged by newer findings showing that only a few hundred have been confirmed. 

So what does all this mean? Basically, that there's still a lot of uncertainty on this topic. Below are the guidelines issued by the U.S. Centers for Disease Control and Prevention (CDC) and supported by the American Congress of Obstetrics and Gynecology.

For women who haven't traveled to an affected country
Although there have been a handful of confirmed cases of Zika virus in the United States, all but one occurred in people who contracted the virus internationally. At this time, the CDC says that women who have not been out of the country do not need to worry.

"If you haven't traveled to countries where Zika is circulating – and the United States is not one of those countries – I think you can rest assured that you're not at risk," says Siobhan M. Dolan, MD, medical advisor to the March of Dimes, and professor of obstetrics and gynecology and women's health at the Albert Einstein College of Medicine in the Bronx.

There is one exception: One case of Zika virus in Dallas has been confirmed as sexually transmitted from a man (who'd been out of the country) to his wife. In a news release issued on February 3, the CDC issued guidelines for pregnant women whose partners may be at risk:

"Until we know more, if your male sexual partner has traveled to or lives in an area with active Zika virus transmission, you should abstain from sex or use condoms the right way every time you have vaginal, anal, and oral sex for the duration of the pregnancy."

For women who have traveled to an affected country but do not have symptoms
Developing a Zika virus infection may be a real concern for pregnant women who have visited a country where the disease is actively spreading. This includes several countries in South and Central America. (The most updated list can be found on the CDC's website.)

In adults, the Zika virus can cause fever, rash, joint pain, and red eyes. If a pregnant woman does not exhibit these symptoms after traveling internationally, says Dolan, she has no reason to panic—but she should still tell her ob-gyn that she's been to affected countries. (Only about one in five people infected with Zika will become ill, and it's unknown whether a woman needs to have symptoms to pass the disease to her baby.)

According to the latest guidelines from the CDC, any pregnant woman who has returned from an affected country in the last two to 12 weeks can have a blood test to determine if she has been infected, whether or not she has symptoms.

A woman should decide together with her doctor whether to be tested, says Lin H. Chen, director of the Travel Medicine Center at Mount Auburn Hospital in Cambridge, Massachusetts, and associate professor of medicine at Harvard Medical School. "If she's very worried – for example, if she's been in a place where a number of other people have been diagnosed – she could consider getting checked,” says Chen, coauthor of an article in the Annals of Internal Medicine about the rapid spread of Zika across the Western Hemisphere.

Testing facilities are limited, and samples must be sent away to a state or federal lab. Getting results can take several weeks. Plus, Dolan cautions, they may not reveal much. "We still don't know how accurate these tests are," she says. "If you test positive, that can be informative, but if you test negative that can't necessarily rule out infection to your fetus."

Dolan stresses that routine prenatal care is important for all pregnant women – whether or not they are at risk for Zika virus. "Most women have an ultrasound at 18 to 20 weeks to look at the fetal anatomy, and you should make sure you have that no matter what," she says. "It's early to identify growth issues [like microcephaly], but it doesn't mean you couldn't see something at that point."

Talk to your doctor about scheduling additional ultrasounds throughout your pregnancy to closely monitor your baby's development. If your doctor finds evidence of possible microcephaly, you can have an amniocentesis (after 15 weeks of pregnancy) to test for the Zika virus in the fluid around your baby.

For women who have traveled to an affected country and have symptoms
Anyone (pregnant or not) who has at least two symptoms of Zika and has traveled to an affected country in the last two weeks should see a doctor. Other mosquito-borne illnesses, like dengue fever and chikungunya, can cause similar symptoms, and doctors are advised to evaluate patients for all three diseases.

If you're pregnant and have symptoms, your doctor should give you a blood test for the Zika virus during the first week you feel ill. Follow the same recommendations for an ultrasound at 18 to 20 weeks, and talk to your doctor about scheduling additional tests to monitor the pregnancy as well. Keep in mind that growth problems often aren't noticeable until the third trimester.

"One of the biggest concerns is that we don't have a vaccine. We don't have a treatment," says Dolan. "So while early diagnosis and early identification [are] important, we are still going to need to understand what this means for these children and what we can actually do."

Precaution is key
If you're pregnant or are trying to get pregnant and you have a trip planned to an affected country, consider postponing it. "The CDC advises this out of an abundance of caution, and most travel clinics and medical organizations are following suit," says Chen. Several airlines and cruise companies are even issuing refunds to pregnant customers or allowing them to change their itineraries without a fee.

If you have to travel to these areas, protect yourself from mosquitoes by wearing long-sleeved shirts and long pants, using an EPA-registered insect repellent, and sleeping in rooms with screens or air-conditioning. (According to the CDC, insect repellents containing DEET, picaridin, and IR3535 are safe for pregnant women when used as directed.)

Taking precautions against mosquito bites is a good strategy even in the United States, says Chen. Even though Zika isn't circulating here yet, health officials predict it will reach southern and mid-Atlantic states. Florida has even declared a state of emergency to ramp up mosquito prevention efforts to try to stay ahead of a potential outbreak.

"There is a small possibility of an outbreak here in the United States, but I think it is unlikely because the health authorities and public health infrastructure here is such that these locations are very aware and taking a lot of precautions to control mosquitoes," says Chen. "At this point, wearing repellent and making sure there are no containers of standing water around your home is really the best advice we have for people living where mosquitoes are active."

Dolan agrees. "Mosquito precautions definitely should be undertaken – not to create hysteria or panic, but because these efforts are easy to do and they're going to maximize your potential to have a healthy pregnancy," she says. "There's no downside, and at the very least it can give you a little peace of mind."

Staying up to date
The news on Zika is constantly changing, but the CDC's web page is updated regularly. There you can find travel advisories, guidelines for pregnant women, and the latest tally of countries and areas affected by the disease.

The World Health Organization also provides information about Zika virus around the world, although it has not gone as far as the CDC in recommending that pregnant women change their travel plans.

You can also find helpful information about mosquito prevention and current risk levels on your state's Department of Health website, especially if you live in a state where mosquito-borne diseases are common.

Staying in touch with these resources can give you reliable information and help you keep your risk of Zika virus in perspective.

"Overall, if you've traveled to those areas or if you have travel in your future, it's worth really thinking about," says Dolan. "But if you are in a place that hasn't had exposure, Zika shouldn't be too high on your list of things to worry about. Taking your folic acid and getting to all of your appointments are the things that are really going to affect your pregnancy outcome."

If you are worrying about the Zika virus constantly (whether or not you may have been exposed), these tips on how to manage Anxiety About Zika During Pregnancy can help you manage your anxieties and get support if necessary.

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Amanda MacMillan

Amanda MacMillan

Amanda MacMillan is a freelance health and science writer who lives in Brooklyn with her husband and bulldog. Her work has been published on CNN.com and in Health, Shape, Prevention, Runner's World, and O, the Oprah magazine.