To report changes in fetal biometrics of patients that developed symptoms compatible with Zika virus infection during pregnancy. 129 patients were enrolled. Inclusion was based on CDC criteria for symptoms suggestive of Zika virus infection during pregnancy. Fetal biometrics and brain were assessed on monthly US scans (256 scans). Biometrics were compared to Intergrowth21 (IG21) standards. Biometrics were also compared to a historical cohort (2011–2012) of 772 healthy Colombian patients with normal fetuses that were used to establish the normality for fetal growth in a comparable cohort. Patients with Zika symptoms were divided into 3 groups based on the moment of clinical presentation as 1 T, 2 T, 3 T. Biometrics were classified if < −2 ZS and −3 ZS cut-offs. Maternal blood PCR was positive for Zika virus in 8 of 10 tested patients. CNS anomalies were detected in 10 cases. No significant changes were detected when comparing biometric Z scores (ZS) between groups. 7.6%1 T, 2.2%2 T and 8%3 T US scans presented HC < 2ZS using Colombian standards (NS). 9% 1 T, 1.1% 2 T, 0% 3 T of the cases presented HC < 2ZS based on IG21, which showed a significant change across groups (p < 0.01).3.6% of 1 T US scans showed HC < 3 ZS by IG21 standards whereas no 2 T or 3 T cases were classified as such (p = 0.06). Using Colombian normality, 4.3%of 1 T, 1.1% of 2 T and 0% of 3 T presented HC < 3ZS (p = 0.1). No differences in the proportion of small AC, FL or EFW were detected. Based on these preliminary results from a cohort of women potentially infected by Zika virus during pregnancy, decreased head growth can be more affected in those cases that presented clinical symptoms earlier. Research on this topic is warranted to clarify the effects of this viral infection in the fetus.