Zika virus was reported in mid-2015 in South America and has since spread throughout the Americas, transmitted primarily by infected mosquitoes (Society for Maternal-Fetal Medicine [SMFM] & American College of Obstetricians and Gynecologists [ACOG], 2016). Approximately 80% of those with Zika virus remain asymptomatic; others report generally mild symptoms such as fever, maculopapular rash, arthralgias, or nonpurulent conjunctivitis lasting from several days to a week (Petersen et al., 2016). It is not known if pregnant women are more susceptible to this infection than nonpregnant women; however, transmission of Zika virus to the fetus has been reported in all trimesters of pregnancy from fetal tissue from early miscarriage to term neonates and placental tissue/amniotic fluid (SMFM & ACOG). The main concern about the Zika virus and pregnancy is the association with the birth defect, microcephaly. The link between microcephaly and Zika has not been proven yet, but due to the outbreak of Zika in Brazil since 2015 with a concurrent increase in babies born with microcephaly, the Centers for Disease Control and Prevention (CDC) and other agencies have been investigating this possible association (CDC, 2016a, 2016b). Until more is known, pregnant women (or women trying to get pregnant and their partners) are being advised to avoid travel to areas where Zika has been reported as active (CDC, 2016a, 2016b). There is risk of sexual transmission of Zika virus and while Zika remains active in the blood for around a week, it has been found in semen longer (CDC, 2016a, 2016b). The virus has been reported in breast milk, but thought to be in such a small amount that it is not likely harmful to the newborn, so women should still be encouraged to breastfeed (SMFM & ACOG).

If Zika virus is suspected (symptomatic women within 2 weeks of travel), maternal serum testing to confirm infection is recommended. This testing is performed in few places so healthcare practitioners should contact their state health department to arrange testing (SMFM & ACOG, 2016). Ongoing fetal surveillance in confirmed or suspected cases through serial ultrasounds is recommended every 3 to 4 weeks and should focus on findings such as intracranial calcifications and microcephaly (SMFM & ACOG). If there is suspicion for fetal infection, an amniocentesis for Zika virus testing of amniotic fluid may be warranted (SMFM & ACOG). This testing also may be offered to women with confirmed Zika virus who do not have evidence of fetal issues (SMFM & ACOG).

Preventing exposure to the virus is critical as there are no prophylactic medications to cure Zika virus or vaccine to prevent transmission (Petersen et al., 2016). If traveling to infected areas cannot be avoided, prevention of mosquito bites should be undertaken. Environmental Protection Agency (EPA)-registered insect repellents are safe for use in pregnancy, including those with DEET, permethrin, picaridin, and IR3535, and should be applied (and reapplied) as per manufacturer's product label (Petersen et al.; SMFM & ACOG, 2016). Mosquitoes that spread Zika virus are active indoors and outdoors, most commonly in the daytime, so other prevention methods include staying in screened-in and/or air-conditioned rooms, treating clothing and gear with permethrin as directed by the product label, and covering skin with long-sleeved shirts and pants (Petersen et al.).

As evidence about Zika virus continues to evolve, refer to the CDC's Web site on this topic for the latest recommendations and information: http://www.cdc.gov/zika/.

References