Zika causes birth defects in one in 10 pregnancies: US study

Francis Osborne
April 5, 2017

About one in 10 women in the United States who were infected with Zika virus while pregnant had a fetus or baby with deformities previous year, USA government scientists said Tuesday.

"Vital Signs: Update on Zika Virus-Associated Birth Defects and Evaluation of All U.S. Infants with Congenital Zika Virus Exposure - U.S. Zika Pregnancy Registry, 2016" was an early release in MMWR, Vol. 66, April 4, 2017.

"Zika continues to be a threat to pregnant women in the United States", CDC Acting Director Anne Schuchat says. All health-care providers, especially obstetricians and pediatricians, need to improve monitoring of these infants. In 2016, almost 1,000 pregnant women from 44 states who completed their pregnancies had some evidence of a recent Zika infection and were at risk of having a fetus or baby with Zika-related birth defects.

The proportion was higher among complected pregnancies with confirmed Zika infection, with about 10 percent reporting had a fetus or baby with birth defects. Of those, Zika-related birth defects were reported in 51 of the pregnancies, or 5 percent.

The CDC counts 1,228 completed pregnancies without known birth defects, 54 babies with Zika-related birth defects and seven pregnancy-related losses since the registry began a year ago.

In addition, while 585 of these 895 infants (65%) were tested for Zika at birth, this leaves about a third who received no Zika testing when they were born.

"Zika virus can be scary and potentially devastating to families". The birth defect rate was even higher, 15%, in those with infections confirmed in the first trimester of pregnancy.

In the current tally, only one-fourth of USA infants born to women suspected to have Zika were given brain imaging tests after birth, meaning it's still possible we might be underestimating the harm Zika may have caused.

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Only Texas and Florida have reported cases of local virus transmission, so women thus far remain at a very low risk in the U.S. However, if a woman is planning a pregnancy, she and her partner should be careful about their travel plans. A baby can be born healthy, with a normal head size, but then develop neurological problems later on. Of those, 24 completed their pregnancy with a fetus or baby that suffered birth defects linked to the virus, the CDC said.

"Brain imaging, for example a brain ultrasound or a CT, is important to look for abnormalities, because we know that some babies have underlying brain defects that are otherwise not evident at birth", she said.

Every mosquito bite carries a risk, Schuchat said, and therefore preventing mosquito bites is critical to keep pregnant women and their babies safe.

The CDC's registry data included all 50 states, Washington, D.C. and territories except Puerto Rico.

As summer approaches, pregnant women or women who are planning on becoming pregnant will want to be extra vigilant about protecting themselves from potential mosquito bites (for the rest of the population, Zika symptoms are generally mild, and include fever, mild rash, itchy, red eyes, and joint pain). Philip said that as of March 27, the health department was waiting for the CDC to deliver Zika test results for about 26 cases, including 16possible infections from 2016 and 10this year. While the Associated Press reported that a Zika vaccine is set to be tested on 2,400 volunteers in the United States over the next few months, the reality is that the warmer months will soon be upon us.

Among pregnant women with confirmed Zika infection, about 1 in 10 had a fetus or baby with birth defects.

Today's report covers 1,297 pregnancies with possible recent Zika infection reported in 44 states in 2016.

Other reports by TheDailyFarc

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