Birth defects seen in 6 percent of US pregnancies with Zika

December 14, 2016 by Mike Stobbe
This 2006 file photo provided by the Centers for Disease Control and Prevention shows a female Aedes aegypti mosquito in the process of acquiring a blood meal from a human host. The Zika virus is transmitted to people primarily through the bite of an infected Aedes aegypti species mosquito. A U.S. study of Zika-infected pregnancies found that 6 percent of them ended in birth defects. The rate was nearly twice as high for women infected early in pregnancy. It's the first published research on outcomes in the United States, and the authors say the findings echo what's been reported in Brazil and other countries with Zika outbreaks. (James Gathany/Centers for Disease Control and Prevention via AP, File)

A U.S. study of Zika-infected pregnancies found that 6 percent of them ended in birth defects. The rate was nearly twice as high for women infected early in pregnancy.

It's the first published research on outcomes in the United States, and the authors say the findings echo what's been reported in Brazil and other countries with Zika outbreaks.

It also showed that the rate of birth defects was the same for women who didn't show any signs of infection during their pregnancy as those that did. That's important because most people who get infected don't have any symptoms, said Margaret Honein of the Centers for Disease Control and Prevention, one of the study's authors. Symptoms include fever, rash, joint pain and red eyes.

"Pregnant women and their health care providers need to understand there is a risk" for infected women who never seemed to get sick, she said Wednesday.

The study came from a U.S. registry that the CDC started earlier this year to monitor pregnant women with Zika. All of the women included were infected while in a Zika outbreak country or had sex with someone who got Zika overseas. Zika is primarily spread through mosquito bites.

Out of the 442 pregnancies, 26 had birth defects linked to Zika, or 6 percent. Among women who were infected in the first three months, the figure rose to 11 percent.

Twenty-one babies were born with birth defects; five of the cases were stillbirths, miscarriages or abortions—the researchers did not say how many of each. Defects included microcephaly, in which a baby's skull is small because the brain hasn't developed properly.

Included in the registry are any foreigners who were in the U.S. when their pregnancy ended. The study did not include the U.S. territory of Puerto Rico, which has been hit hard by Zika.

The CDC study was published this week by the Journal of the American Medical Association. Honein said the best estimates now are that 10 to 15 percent of first-trimester infections develop microcephaly or certain other problems that can be diagnosed at birth.

Another study this week in the New England Journal of Medicine, done in Brazil by doctors at the University of California, Los Angeles, found that among 117 infants born to Zika-infected moms, 42 percent had "grossly abnormal" clinical or brain imaging findings. That included four infants with microcephaly, but also cases in which the harms caused were not clear.

Scientists are still trying to determine the full range of birth defects that Zika may cause, including whether there are some that may not be diagnosed for months or years.

Explore further: In Colombia, deformed babies quadrupled amid Zika crisis: CDC

More information: Margaret A. Honein et al. Birth Defects Among Fetuses and Infants of US Women With Evidence of Possible Zika Virus Infection During Pregnancy, JAMA (2016). DOI: 10.1001/jama.2016.19006

Related Stories

In Colombia, deformed babies quadrupled amid Zika crisis: CDC

December 9, 2016
Four times the number of babies born with skull deformities linked to Zika virus were reported in Colombia this year following the outbreak of the mosquito-borne infection, said a US government report Friday.

Zika linked to birth defects in six US cases

June 17, 2016
The Zika virus has been linked to birth defects in the fetuses and babies of six women in the United States who were infected while pregnant, US health officials said Thursday.

CDC: 3 babies with Zika-linked birth defects born in US

June 16, 2016
Three babies with Zika-linked birth defects have been born in the U.S., the government reported Thursday in its first accounting of outcomes for pregnant women infected with the virus.

Zika infections late in pregnancy led to no defects in study

June 15, 2016
Women infected with the Zika virus late in their pregnancies had babies with no apparent birth defects, according to a study in Colombia that seems to confirm that the greatest risk to infants comes early in pregnancy.

CDC: Birth control needed in Puerto Rico during outbreak

March 25, 2016
Health officials say tens of thousands of IUDs and other forms of birth control are badly needed in Puerto Rico to help prevent unintended pregnancies during an outbreak of Zika, the tropical disease linked to birth defects.

US declares Zika public health emergency in Puerto Rico

August 13, 2016
US health authorities on Friday declared a public health emergency in Puerto Rico due to the outbreak of Zika, which has now infected more than 10,000 people.

Recommended for you

Blood signature could improve early tuberculosis diagnosis

June 19, 2018
A gene signature in the bloodstream could reveal whether someone is going to develop active tuberculosis (TB) disease months before symptoms begin. Such a signature has now been developed by a team led by the Francis Crick ...

Scientists uncover a factor important for Zika virus host species restriction

June 19, 2018
Princeton University researchers Qiang Ding, Alexander Ploss, and colleagues have identified one of the mechanisms by which Zika virus (ZIKV) circumvents immune control to replicate in human cells. The paper detailing this ...

Toothpaste and hand wash may contribute to antibiotic resistance

June 19, 2018
A common ingredient in toothpaste and hand wash could be contributing to antibiotic resistance, according to University of Queensland research.

Combining different malaria vaccines could reduce cases by 91 percent

June 19, 2018
Using two experimental anti-malarial vaccines, which work in different ways, can greatly reduce the number of malaria infections in animal studies.

Children's immune system could hold the key to preventing sepsis

June 19, 2018
Children's immune systems could hold the key to preventing life-threatening infections and sepsis, a new study has revealed.

Beware of getting a tattoo if your immune system isn't up to scratch, doctors warn

June 18, 2018
Getting a tattoo may have some unexpected complications if your immune system isn't up to scratch, warn doctors in the journal BMJ Case Reports.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.