Relative Risks and Reasonable Responses to the Zika Virus in Pregnancy – Part 2

By Rebekah Wheeler, RN, CNM, MPH

By Muhammad Mahdi Karim ( Facebook Youtube - Own work, GFDL 1.2,

By Muhammad Mahdi Karim (
FacebookYoutube – Own workGFDL 1.2,

The Zika virus and its potential effect on pregnant people have been hot topics for the past several weeks.  News headlines, health alerts, social media and more have been busy offering up information and suggestions about this virus that no one seemed to know about before 2016.  Filtering fact from fiction and fear mongering is important and childbirth educators and other birth professionals are in a great position to share evidence based information and facts with the families they work with.  Last Tuesday, Certified Nurse Midwife and public health specialist Rebekah Wheeler shared information about what exactly is the Zika virus – providing all the facts about what it is and what it isn’t.  Today, Rebekah talks about the Zika risk in relation to other known risks that may affect pregnant people.  After reading these two posts, you should feel confident in understanding the basics of the Zika virus, what families can do to reduce their risk and how  they can understand those risks in relation to other risks they may also face.  – Sharon Muza, Community Manager, Science & Sensibility

The Big Picture: Pregnancy and Risk

The truth is, we live with risk all the time.  Pregnant people are regularly warned about threats to their fetus’ well-being, from smoking to sushi.  Providers say “don’t do xxx” in pregnancy, and people fear it and avoid it, even without knowing the real size or severity of the risk.  I believe that it is highly problematic that the majority of prenatal care providers in the US don’t take the time to differentiate between common risks with proven, causal, significant impacts and rare risks with unusual or unproven negative outcomes.

Breaking down the “smoking to sushi” phrase I used above, for example, illustrates the vast difference in scale and severity of different risks in pregnancy.  Smoking has been proven to increase risks for poor fetal growth, preterm delivery, cerebral palsy, asthma and SIDS (Tobacco Use and Pregnancy. 2015). The impact is studied, proven, real, and severe.  Sushi, on the other hand, is warned against for its possible risk of increased exposure to listeria bacteria, and the severe food-borne illness that can result in hospitalization, miscarriage and fetal malformations (Janakiraman, V., 2008).  The last time that freshly-made sushi was implicated in a case of listeriosis in pregnancy in the US, however, was more than eight years ago (The Prevalence of Listeria in Food and the Environment)).  The advent of faster and safer fast-freezing methods for raw fish have dramatically decreased the likelihood of listeria exposure, implicating prepackaged and processed foods far more often than fresh foods  (CDC. 2013), (Miya, S., et al.2010), but providers aren’t keeping us up to date on size or severity of risk.

As a prenatal care provider, I regularly talk about risk with my patients and their partners.  I think every patient deserves to be given real data on the frequency of a risk and the severity of the conditions that might arise if they are exposed to this risk.  Some risks are rare but severe, like getting a first exposure to the Herpes Virus in pregnancy.  Some are common but have small impact and are reversible, such as having anemia.  In flu season, for example, I want pregnant patients to know that influenza infection in pregnancy results in much more severe illness than in non-pregnant adults.  This can mean hospitalization, possible miscarriage or fetal loss, or in some cases even fetal abnormalities.  Similar conversations should be had about CMV, Parvovirus, Toxoplasmosis, Rubella and others. As with Zika, we know our risks of contracting them is rare, and we go about our lives without any sense of overwhelming fear.  Many of these are actually airborne or food borne, making them much easier to transmit and contract than a mosquito-vector virus such as Zika.  In order to avoid undue risk, we make loose rules that could help avoid most exposures, and we’re comfortable with that.

When counseling about exposure risk, I talk about the relative risks of vaccination versus contracting flu, and then I let my patients make the decision they think is best for them.  I respect that different sets of parents will have different comfort levels when it comes to abstract and rare risks.  Each individual or couple will interpret risk differently, and have different values around risk exposure and avoidance.

By Gideon - originally posted to Flickr as chavette 2, CC BY 2.0,
By Gideon – originally posted to Flickr as
chavette 2, CC BY 2.0,

In my view, pregnancy is a period of practice in making choices around risk versus benefit.  This is practice for being a parent, for risk doesn’t end when a child is born.  Quite to the contrary, parents are now thrown into a world of decisions about breast vs bottle-feeding, vaccination schedules, preschool vs daycare…the list goes on and on.  Parents are constantly calibrating risks and benefits and making decisions based on the best data available to them.  Part of learning to think about risk is to check in with themselves about whether doing or not doing something will cause more anxiety.  In choosing whether or not to screen for genetic abnormalities such as Down Syndrome, for example, I see many families who decide that the emotional risk of a false positive outweighs their worries about having a baby with any genetic problem.  They opt against testing.  Other couples know that the reassurance of a negative test is important to them, and choose to screen.  Risk means different things to different people.

I do not write this to terrify soon-to-be parents.  I write this to put Zika into the greater context of risk.  It is a new risk, in that most of us had never heard of it before last month, and the frequency and impacts are unknown, which is scary.  But there are factors about Zika that make it unlikely to be a frequent risk, and that also point to a very small likelihood of it causing microcephaly in most cases:

  • Zika has been around for a long time without migrating to the US.
  • We have a great public health infrastructure well-equipped at handling cases of very similar diseases, such as Dengue and Chikungunya.
  • We haven’t seen microcephaly in any of the other countries where there have been outbreaks.  This suggests that there are other or additional factors that led to the cases in Brazil.
  • There are effective ways to avoid getting exposed to bites from mosquitoes that carry the virus.
  • There is only one mosquito species confirmed to carry the virus, and their geographical scope is limited.

Thus, it is my prediction that Zika will become like many other risks in pregnancy: rare and mostly avoidable.  Other examples of similarly-categorized risks abound.  Contracting chickenpox for the first time in pregnancy, for example, is linked to a 2% risk of congenital varicella syndrome, which is serious.  Thus, pregnant people who have never had chickenpox or whose immunity has worn off are not told “never leave your house in pregnancy”.  Instead, they are advised not to visit with any children with known rashes or who are known to have the disease.  As mentioned above, smoking is associated with a number of fetal problems.  But we don’t tell people never to go into public and to stay miles away from any lit cigarette.  Instead, we take a reasonable approach and give support around smoking cessation for pregnant patients and their partners.  Response to an individual risk ought to be correlated to the likelihood and impact to exposure.  

It is my belief that we should approach Zika in a similar way: avoid the behaviors to maximize risk of exposure and practice behaviors that would minimize risk. While it is important to make informed choices around minimizing risks, it is also important not to become overwhelmed by the perception of risk that far outweighs that relative risk of something like Zika. The great challenge to those of us who are parents is to live full lives without being incapacitated by the fear of risk.  Parenting means making an unending series of decisions about risk, and learning to make them without undue anxiety or loss of a sense of the fullness and potential of life.   The media love this story, because it is intense and full of unknowns.  It is hard to keep perspective when the media is in a frenzy, but remember that there is much we do not know, and what we do know so far points towards your personal risk being negligible.  If we start to see an uptick in cases of Zika in this country, invest in bug spray, turn on your air conditioner, and cover up.  But now families should know better than to let sensationalist panic feed their own.

What are you telling your families about the Zika virus and its impact on pregnant people?  Have you been fielding a lot of questions about this in your classes and with your clients?  Do you have some additional information to add to these articles that our readers would find helpful? Please share in our comments below. – SM.


Janakiraman, V. (2008). Listeriosis in pregnancy: diagnosis, treatment, and prevention. Rev Obstet Gynecol1(4), 179-85.Centers for Disease Control and Prevention (CDC. (2013). Vital signs: Listeria illnesses, deaths, and outbreaks–United States, 2009-2011. MMWR. Morbidity and mortality weekly report62(22), 448.

Miya, S., Takahashi, H., Ishikawa, T., Fujii, T., & Kimura, B. (2010). Risk of Listeria monocytogenes contamination of raw ready-to-eat seafood products available at retail outlets in Japan. Applied and environmental microbiology,76(10), 3383-3386.

The Prevalence of Listeria in Food and the Environment. (n.d.). Retrieved February 29, 2016, from

Tobacco Use and Pregnancy. (2015). Retrieved February 29, 2016, from

About Rebekah Wheeler

© Rebekah Wheeler
© Rebekah Wheeler

Rebekah Wheeler, RN, CNM, MPH, works as a full-scope Nurse-Midwife in San Francisco.  She moved to the Bay Area in 2011, after completing her MPH and MSN at Yale University.  Before becoming a midwife, she worked in international women’s health programming and research in Tanzania, Malawi, South Africa and Mexico. She is the founder of the Malawi Women’s Health Collective, a small non-profit she created while on a Fulbright scholarship. Rebekah has served on the boards of the California Nurse-Midwifery Association, Planned Parenthood of Rhode Island and the Women’s Health and Education Fund of Southeastern Massachusetts.   


Thanks Rebekah, for this AMAZI

March 6, 2016 07:00 AM by Evelyn Funke Folorunsho, RM,IBCLC,LCCE
Thanks Rebekah, for this AMAZING write up on Zika Virus, very educative and a tension breaker! I have no contribution but to commend the good job.

nice followup on the actua

March 9, 2016 07:00 AM by Wednesday Wrap Up March 9 | Andrea Lythgoe Doula Salt Lake City Utah
nice followup on the actual risk of the Zika virus, and on risk in pregnancy in general. If you missed Part 1 of the series, please go read that one, [?]

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