Zika and Birth Defects

Most of us have probably heard of Zika and know it is most often transmitted through mosquito bites and unprotected sex with infected people.  Zika is also linked to birth defects.

This is not a blog post about Maryland law or medical malpractice.  But we are interested in the health of babies. This is something that people need to understand.

Zika Virus


Zika is a virus transmitted primarily by Aedes mosquitoes. It became a public health emergency in 2016 due to its potential link to birth defects in infants born to mothers infected with the virus during pregnancy. The virus can also be sexually transmitted and can cause other health problems, such as fever, rash, joint pain, and conjunctivitis.

The Zika virus was first identified in 1947 in the Zika forest of Uganda, but it did not pose a significant public health threat until it spread to Brazil in 2015. As the virus spread to other countries, including the United States, health officials became increasingly concerned about the potential link between Zika and birth defects.

In response to the outbreak, public health officials issued travel warnings, advised pregnant women to take precautions to avoid mosquito bites, and recommended that men who have traveled to areas with Zika use condoms or abstain from sex for a period to prevent the sexual transmission of the virus.

Researchers have been working to develop a vaccine for Zika, but as of early 2023, no vaccine has been approved for widespread use.

Disguised as Benign

While Zika is usually not life-threatening, the problem is that many infected people will not even know it. Often, the Zika virus will only cause very mild symptoms, if any at all. An infected person may have a fever, rash, headache, joint pain, red eyes, and/or muscle pain that lasts only a few days up to a week.

Usually, an infected person will not become sick enough to require medical care, although in rare cases, they might. After the virus subsides, the infected person will usually be protected from future infections. Unfortunately, there is no vaccine, treatment, or cure for Zika, and to protect yourself, you must take preventative steps to prevent mosquito bites, especially if you are traveling to an area where the virus is known to be such as Africa, Southeast Asia, and the Pacific Islands.

Zika and Birth Defects

What you may not know, however, is that if you are pregnant and become infected by the Zika virus, it could also infect your baby and cause birth defects. That’s right, Zika has been associated with several birth defects and injuries, and a lot of research is being conducted to learn more about it. When a fetus is exposed to the virus before birth, that exposure causes Congenital Zika syndrome.

This could be because of a mosquito bite or from the mother having unprotected sex with an affected partner. Congenital Zika syndrome encompasses a unique number of birth defects found in fetuses and babies infected by Zika in utero. For one, it is known that microcephaly can be caused by an infection during pregnancy. Additionally, infection during pregnancy has been associated with miscarriages, stillbirth, and Guillain-Barre syndrome. When it comes to Congenital Zika syndrome, however, it is defined by five distinct features, including:

  • Microcephaly- Studies found that infants born to mothers infected with the Zika virus during pregnancy were at risk of microcephaly, a birth defect in which the baby’s head is smaller than expected, and other neurological disorders. In addition to microcephaly, the virus has been linked to other birth defects, such as eye abnormalities, hearing loss, and impaired growth.
  • Distinct pattern of brain damage resulting in brain tissue decrease
  • Scarring and/or pigment changes in the eye
  • Limited range of motion in joints
  • Excess muscle tone that results in body movement restriction
  • Cerebral palsy

It is widespread for babies infected before birth to have damage to the area of the brain responsible for vision that could affect their visual development and/or eye damage. Additionally, microcephaly is not necessary for a baby to have eye damage. Babies can have eye damage with or without microcephaly. When it is known that the baby has been infected by Zika, it is imperative to have the proper tests and screenings done to check for eye problems even if the baby seems healthy.

Cerebral Palsy and Zika

Besides all these severe birth defects known to be associated with congenital Zika, you also may not know it has recently been associated with cerebral palsy. A recent study looked closely at this association in children with cerebral palsy likely related to congenital Zika to assess their neurological and neurodevelopmental features. Specifically, the researchers collected data using Bayley-III Scales of Infant and Toddler Development and other tests and assessments in 82 children with cerebral palsy associated with congenital Zika.

After collecting data from these children, including measurements of physical, motor, sensory, and cognitive development, the researchers performed statistical analyses to look for any correlations with congenital Zika. The results were troubling, as strong correlations were discovered in children with cerebral palsy and probable congenital Zika. Nearly 62% of the children had severe congenital microcephaly, 63.4% had epilepsy, 93.2% lacked expected postural reactions, 94.7% showed abnormal persistence of primitive reflexes, and 97.6% exhibited severe neuroimaging abnormalities, primarily calcifications. Of most concern, however, was that 96.3% of the children had spastic cerebral palsy, a very severe form of it. Additionally, researchers observed very low cognitive, language, and motor developmental performance scores in children with congenital Zika. Lastly, a statistically significant correlation was discovered between the cognitive and motor score of a child with congenital Zika and head circumference.

These results led to the conclusion that congenital Zika may be associated with spastic cerebral palsy resulting in severe neurodevelopmental impairment and a low prognosis for the likelihood of independent walking. Additionally, the results suggest that given the correlation between head circumference and cognitive and motor scores, head circumference could be a prognostic marker among children with cerebral palsy associated with congenital Zika. The researchers who conducted this study hope that while the results were strictly observational, given the new association with spastic cerebral palsy, perhaps it will encourage the establishment of goals for rehabilitating children with probable and confirmed congenital Zika as to help identify priority health services.

Zika Increase Risk

While congenital Zika is known to be associated with microcephaly, this is the first study to find it is also likely associated with spastic cerebral palsy. It is important to know that not all babies born with a congenital Zika infection suffer from these problems. But it significantly increases the likelihood. Researchers worldwide are working hard to better understand the relationship between the Zika virus and birth defects. Still, if you are pregnant, taking the proper precautionary steps is imperative to avoid contracting a Zika infection if you are in an area or traveling where there have been known cases.

If you have been in an area where Zika is prevalent or just recognize the symptoms and you are pregnant, be sure to get checked immediately. While researchers are uncertain, the available evidence suggests that if a woman who is not pregnant contracts a Zika infection after the infection clears from her blood, it should not affect future pregnancies. Additionally, you should be protected from future Zika infections after the infection has cleared.