Zika Virus and the Risk of Birth Defects


Zika virus and birth defects male infertility

Infection with the Zika virus is a new and alarming concern for couples who are either pregnant or trying to conceive.  Although the virus was first discovered in the 1940’s in a monkey living in the Zika forest of Uganda, the recent rapid spread of the virus throughout the Americas has put it firmly on the radar of the fertility community in the United States.  And since many couples either live or vacation (and often honeymoon) in tropical or subtropical areas where the risks are highest, this has resulted in quite a bit of anxiety compounded by confusion.

The primary cause of spread of the Zika virus is through a bite by the Aedes mosquito, which is generally found in tropical or subtropical regions.  This Aedes mosquito is also known to transmit other diseases such as dengue fever, Yellow fever, and chikungunya.  Once infected, person-to-person transmission of the virus can occur through sexual intercourse, blood transfusions, and placental transfer from mother to fetus.

Developmental Risks of the Zika Virus


From a fertility standpoint, the primary concern of the Zika virus is the risk of developmental defects in the fetus of an infected mother.  The most common developmental concern is the risk for microcephaly, in which the head (and brain) of the baby remains abnormally small.  This is generally associated with a range of neurologic problems which can include seizures, trouble with feeding, speech, and sitting/crawling/standing.  Hearing and vision can be affected as well as overall intellectual development.  Infection with the Zika virus during pregnancy can also increase the risk of fetal death and miscarriage.

There is currently no treatment available for fetuses who are infected with the Zika virus, so the best defense is prevention.  Transmission to the fetus can occur both before or after a pregnancy has been established, so preventative measures must be taken by women who are either already pregnant and those who are planning a pregnancy in the near future. 

Preventing Zika-Related Birth Defects


As discussed above, the two primary ways that women can be infected with the Zika virus (outside rare instances like needing a blood transfusion) is:

1) A bite by an Aedes mosquito

2) Transmission by sexual partner


Transmission by mosquito bite

Most residents of the United States currently do not live in an area where documented transfer of the Zika virus to people by mosquito bites has been detected, so their primary risk is traveling to an area where there is an endemic risk.  However, two states (Florida and Texas) have had isolated cases of Zika transmission by mosquito bites.


The CDC has a published a map of the world showing the areas of risk for Zika transmission by mosquito bites.


Within the United States, as mentioned earlier, the risk of contracting Zika by a mosquito bite is currently low, though a few documented cases have occurred in Florida and Texas.  This list is certain to grow, as the potential range of the Aedes mosquito within the United States is relatively large.  To understand this future risk, one must know that there are two forms of the Aedes mosquito: aegypti and albopictus.  The Aedes aegypti prefer to feed on people and therefore are more likely to transfer the Zika virus.   The Aedes albopictus mosquito also feeds on animals in addition to humans, and is therefore less likely to transmit harmful viruses to people.  Fortunately, the Aedes aegypti has a smaller potential range within the United States, though it is still fairly broad.  The following CDC link shows a map with the potential range of each Aedes mosquito for 2016 in the United States.  Remember, this is the potential range for the mosquito, but documented Zika transference by mosquito bites has only been reported in Texas and Florida at this time.  Another point to consider though, is that this estimated range for the mosquitos is likely to increase with time due to progressive global warming.

Preventing Transmission


Avoiding Travel

The #1 CDC recommendation for pregnant women or women planning on establishing a pregnancy in the near future is to avoid travel to endemic areas if at all possible.


Prevention of Bug Bites

If a woman must travel to an endemic area, taking steps to prevention bug bites is extremely important. The CDC has 3 main recommendations:

          1) Use EPA-registered mosquito repellents that contain at least 20% DEET

          2) Cover exposed skin

          3) Avoid Bugs where you are staying

Delaying conception after traveling to an endemic area


In September 2016, the American Society of Reproductive Medicine (ASRM) published new guidelines which they modified from the CDC, FDA, and WHO guidelines.  The full guidelines are attached in a PDF below and I strongly recommend that couples read them if they either live in or plan on traveling to an endemic Zika area.

It must be noted that the strategies listed in these guidelines cannot guarantee a total elimination of risk for Zika-related birth defects, but they are currently the best recommendations available to minimize these risks.

A summary of a few of the recommendations for men or women who have recently traveled to an endemic Zika area


1) If the man or woman had symptoms consistent with or a documented infection by the Zika virus

a) Then they should use condoms or practice abstinence for 6 months. 

 b) Abstinence includes avoiding vaginal or anal intercourse, oral sex, or the sharing of sex toys.

c) Symptoms consistent with possible infection with the Zika virus include:

                 a) Fever >38 degrees C   b) Malaise   c) Joint pain   d) Headache   e) Conjunctivitis   f) Skin rash


2) If the man or woman had possible exposure but no clinical illness

a) Recommend consider testing for the Zika virus within 2 week of suspected exposure and then again at least 8 weeks after exposure. 

b) If both tests are negative, then can consider discontinuing abstinence and/or condom use. 

A summary of a few of the recommendations for men or women living in endemic areas

Recommendations for couples living in endemic Zika areas are less well-formed, and include talking with your health care provider about the risks of attempting reproduction and avoiding exposure to mosquito bites.  Obviously even in the highest risk endemic areas, the vast majority of children are born without any Zika-related birth defects.  However, since the consequences are so potentially devastating, it is worthwhile to discuss the risks and devise a plan to minimize the chances of contracting Zika during a pregnancy.

The Latest Guidelines

As mentioned above, like Zika virus problem itself, the official guidelines for Zika diagnosis, management, and prevention have been changing rapidly.  This website tries to stay up-to-date on the latest recommendations, but it is never a bad idea to check out the CDC and ASRM guidelines to make sure that there have not been any recent changes or updates.

Testing for the Zika virus


Testing for the Zika virus has not been standardized and is rapidly evolving, this creating further uncertainty regarding the effectiveness of the ASRM guidelines above.  LabCorp currently offers a “Zika Virus Comprehensive Profile” which can be performed on either blood or urine specimens [CPT 87798(x2)].  ICD-10 diagnosis code to use is Z11.5.