New UCLA-led research finds that Zika-linked abnormalities that occur in human fetuses are more extensive -- and severe -- than previously thought, with 46 percent of 125 pregnancies among Zika-infected women resulting in birth defects in newborns or ending in fetal death.
The study, published in the New England Journal of Medicine, suggests that damage during fetal development from the mosquito-borne virus can occur throughout pregnancy and that other birth defects are more common than microcephaly, when babies are born with very small heads. Further, these defects may only be detected weeks or months after the baby is born, said Dr. Karin Nielsen, the study's senior author and a professor of clinical pediatrics in the division of pediatric infectious diseases at the David Geffen School of Medicine at UCLA and Mattel Children's Hospital.
"This means that microcephaly is not the most common congenital defect from the Zika virus," Nielsen said. The absence of that condition does not mean the baby will be free of birth defects, she added, because "there are problems that are not apparent at birth" and such difficulties may not be evident until the age of six months.
"These are sobering results," Nielsen said.
The results are a follow-up to a smaller Brazilian study published in March that used molecular testing to find an association between Zika infection in pregnant women and a series of serious outcomes that included fetal deaths (miscarriages and stillbirths), abnormal fetal growth and damage to the central nervous system. This is the largest study to date of Zika-affected pregnancies in which the women were followed from the time they were infected to the end of their pregnancies. All the women were enrolled before any abnormalities in their pregnancies had been identified.
The new study was based on a larger sample size of 345 women in Rio de Janeiro, Brazil, who were enrolled from September 2015 through May 2016. Of those women, 182, or 53 percent, tested positive for Zika in the blood, urine or both. In addition, 42 percent of the women who did not have Zika were found to be infected with chikungunya, another mosquito-borne virus; 3 percent of Zika-positive women also had chikungunya.
From there, the researchers evaluated 125 women infected with Zika and 61 who were not infected with the virus who had given birth by July 2016. The previous study was based mainly on prenatal ultrasound findings; by contrast, the current research evaluated infants from Zika-affected pregnancies through physical examination and brain imaging. Among the findings:
•There were nine fetal deaths among women with Zika infection during pregnancy, five of those in the first trimester.
•Fetal deaths or abnormalities in the infants were present in 46 percent of Zika-positive women, contrasted with 11.5 percent of Zika-negative women.
•Forty-two percent of infants born to the Zika-infected mothers were found to have microcephaly, brain lesions or brain calcifications seen in imaging studies, lesions in the retina, deafness, feeding difficulties and other complications.
The risks occurred at all stages of pregnancy: 55 percent of pregnancies were affected in the first trimester, 51 percent in the second trimester and 29 percent in the third trimester.
The researchers noted that they examined the babies during their early infancy, when "more subtle neurologic manifestations of disease are not identified." So follow-up examinations could turn up evidence of more neurologic diseases that couldn't be detected earlier in the babies' lives.
"Our data show that the risk of severe adverse pregnancy and infant outcomes after maternal Zika infection was substantial," the authors wrote.
Supporting the study were the Departamento de Ciência e Tecnologia do Ministério da Saúde do Brasil; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES/ 88887.116627/2016-01,) and the National Institute of Allergy and Infectious Diseases/National Institutes of Health grant AI AI28697.
Source: University of California, Los Angeles Health Sciences
Stay prepared and protected with Infection Control Today's newsletter, delivering essential updates, best practices, and expert insights for infection preventionists.
Reducing Hidden Risks: Why Sharps Injuries Still Go Unreported
July 18th 2025Despite being a well-known occupational hazard, sharps injuries continue to occur in health care facilities and are often underreported, underestimated, and inadequately addressed. A recent interview with sharps safety advocate Amanda Heitman, BSN, RN, CNOR, a perioperative educational consultant, reveals why change is overdue and what new tools and guidance can help.
New Study Explores Oral Vancomycin to Prevent C difficile Recurrence, But Questions Remain
July 17th 2025A new clinical trial explores the use of low-dose oral vancomycin to prevent Clostridioides difficile recurrence in high-risk patients taking antibiotics. While the data suggest a possible benefit, the findings stop short of statistical significance and raise red flags about vancomycin-resistant Enterococcus (VRE), underscoring the delicate balance between prevention and antimicrobial stewardship.
What Lies Beneath: Why Borescopes Are Essential for Verifying Surgical Instrument Cleanliness
July 16th 2025Despite their smooth, polished exteriors, surgical instruments often harbor dangerous contaminants deep inside their lumens. At the HSPA25 and APIC25 conferences, Cori L. Ofstead, MSPH, and her colleagues revealed why borescopes are an indispensable tool for sterile processing teams, offering the only reliable way to verify internal cleanliness and improve sterile processing effectiveness to prevent patient harm.
The Next Frontier in Infection Control: AI-Driven Operating Rooms
Published: July 15th 2025 | Updated: July 15th 2025Discover how AI-powered sensors, smart surveillance, and advanced analytics are revolutionizing infection prevention in the OR. Herman DeBoard, PhD, discusses how these technologies safeguard sterile fields, reduce SSIs, and help hospitals balance operational efficiency with patient safety.
Targeting Uncertainty: Why Pregnancy May Be the Best Time to Build Vaccine Confidence
July 15th 2025New national survey data reveal high uncertainty among pregnant individuals—especially first-time parents—about vaccinating their future children, underscoring the value of proactive engagement to strengthen infection prevention.