Introduction: Early prenatal diagnosis of chromosomal abnormalities requires invasive techniques, including chorionic villous sampling (CVS) and amniocentesis (AMC) in order to acquire, culture and kayotype cells from fetuses at high risk for these abnormalities based on sonographic and biochemical markers present after week 11. We report our experience through June 2016.Design: Descriptive, longitudinal study. Setting: Instituto Latinoamericano de Salud Reproductiva (ILSAR), Lima, Peru. Participants: First and second trimester of pregnancy fetuses. Interventions: Results of the study of 400 first and second trimester fetuses at high risk for chromosomal abnormalities (greater than 1/270 initially or 1/100 starting in 2012) based on Spain Fetal Test database and the results of biochemical markers (combined risk). Fetal karyotype analysis was performed on samples obtained from 338 genetic...