Pregnancy delays can have a substantial effect on reducing cases of microcephaly but can exacerbate the Zika virus outbreak if the timing and duration of the delay is insufficient. To be effective, a strategy to delay pregnancy should be initiated early in a Zika outbreak, should last longer than 6 months, and should be combined with mosquito-control measures. The findings are published in Annals of Internal Medicine.
Prenatal exposure to Zika virus has been linked to microcephaly, other serious neurological conditions, and fetal death. As such, health officials in Zika-prone areas have advised women to postpone pregnancy. However, the recommended duration of pregnancy delay varies from place to place and there is little action from governments to facilitate adherence. Since a surge in pregnancies is likely to occur after a period of abstention, there is an urgent need to evaluate the effectiveness of pregnancy delay policies for mitigating Zika virus infection.
Researchers developed a data-driven disease transmission model to evaluate the effectiveness of pregnancy delay recommendations in reducing the incidence and prevalence of prenatal Zika virus infection in Colombia. The assumption was that the effectiveness of mass pregnancy delays would depend on the duration of the delay, the population-level adherence to the policy recommendation, and the timing of the initiation relative to peak incidence of infection within the community. The researchers found that pregnancy delay strategies are more effective if they last more than 6 months and start early in an outbreak. Anything less would be likely to exacerbate prenatal exposure due to the surge in pregnancies after the period of abstinence.
Article: Mitigating Prenatal Zika Virus Infection in the Americas, Martial L. Ndeffo-Mbah, PhD; Alyssa S. Parpia, MPH; and Alison P. Galvani, PhD, Annals of Internal Medicine, doi:10.7326/M16-0919, published online 26 July 2016.