With the increasing news coverage of Zika and it’s reported link to the birth defect microcephaly we’ve received a number of reader questions about microcephaly and what it actually means for children born with the condition. We reached out to infectious disease specialist, Dr. Judy Stone, to answer some of your questions.
What does microcephaly actually mean (Is the brain small, does it stop growing at a certain stage, is part of the brain missing)?
Microcephaly literally means an abnormally small head. Both the skull and brain are abnormally small with microcephaly, and X-ray studies often show abnormal calcified areas in the brain and lack of normal development.
Is Zika the only way a baby can be born with microcephaly or are there other risk factors?
Microcephaly has been associated with many infections as well as genetic abnormalities, malnutrition, or exposure to certain toxins. It already happens very rarely in the U.S. due to the level of nutrition and prenatal care most women receive (although even with good nutrition and proper prenatal care, microcephaly can still occur due to certain genetic factors or infections). Even in Brazil, the “epidemic” of this birth defect is thought to be <1%. Some researchers think that some of the sudden apparent increase reflects changes in reporting rather than new illnesses. It’s also important to know that the link right now is just correlated with Zika, there hasn’t yet been a cause and effect relationship proven, but it’s enough to raise alarm bells.
Is a pregnancy more vulnerable to microcephaly at certain stages than others?
The embryo is most at risk in the first trimester. This isn’t just with Zika, but is also the same with other infections or exposure to environmental toxins. The first trimester is the most risky for developing brains and risk goes down as the fetus matures.
How likely is it that a pregnant woman, infected with Zika, will deliver a baby with microcephaly?
Current estimates are that <1% of the babies of an infected woman will have microcephaly.
One of the problems is that we don’t have good diagnostic tests for Zika, except in places like the CDC. So right now, we don’t know if the babies with microcephaly developed it as a direct result of exposure to Zika in the womb, or if it is perhaps a combination of other infections or environmental conditions. Dengue, Chikungunya, and even Yellow Fever are heavily circulating in South America right now, so there could be a connect there, not just with Zika.
Another issue is that ultrasounds are unlikely to detect the abnormality until 24-28 weeks pregnancy. Sometimes, the defect doesn’t become clear until after birth.
Are there any treatments available in utero if microcephaly is detected on an ultrasound?
There are no treatments that would change the outcome for a fetus that has already developed microcephaly in utero. In the United States, if a woman would want to terminate the pregnancy if microcephaly was present, the stage at which the defect is detectable is outside what is legally allowed for abortions in the US. In South America women don’t have access to abortion in a clinical setting and many seek to terminate a pregnancy, even at that late stage, in unsafe and clandestine settings, which may kill them.
Another important issue is that the Gulf states, where Zika is most likely to occur in the U.S., are also the most strident in limiting access to contraception, especially for teens and poor women who rely more on public assistance and Planned Parenthood for care. Advising poor women to avoid pregnancy due to the risk of microcephaly, when they have limited access to contraception, shifts the responsibility unfairly onto them.
What is the life expectancy of a baby born with microcephaly? Are there any treatments or therapies? What, if any, difficulties can babies born with microcephaly face as they grow up?
Some cases of microcephaly can be mild, and not affect the length of life. If microcephaly is present the child will likely have learning and neurologic difficulties, but there is a spectrum, or range of manifestations.
In severe cases, the infant may not live very long. Most commonly, there will be severe mental retardation. Seizures, deafness, and blindness are also major, serious complications, as are difficulties with movements (e.g., standing, walking, balance).
Do we know if the risk is only if Zika is contracted during pregnancy or if the woman has ever had Zika (i.e.: A woman goes to Jamaica on vacation, contracts the virus unknown to her, then becomes pregnant two years later)?
At this time, we have no reason to believe that a Zika infection would be chronic or have any influence on a later pregnancy. With Zika and the related viral infections, you become infected, may or may not become ill (the majority of cases are asymptomatic) and the illness, or active infection, lasts about a week.
The only exception to this is that there have been two cases where men have transmitted infection sexually. It’s thought that rarely, the Zika virus can hide in the testes, and only become apparent some time later. Public Health England has just advised men to wear condoms for about a month after traveling in countries where Zika has spread, or for six months if they had unexplained fevers or Zika. CDC has not followed suit.
How can I protect myself and my unborn baby?
There are several nasty viral infections increasing in the U.S., as well as globally. It is increasingly important to carefully protect yourself and your children by using permethrin on your clothes and shoes, and 20-30% DEET or picaridin on limited areas of exposed skin. These efforts will also help protect against tick-borne infections like Lyme.
Staying in air-conditioned or screened in areas, or using a mosquito net are helpful if you are in vulnerable areas. One simple measure that everyone should do is to eliminate any standing water both inside and outside your homes, to reduce mosquito breeding areas.
Read more about Zika on an earlier post from Dr. Waleed Al-Salem.