Since its discovery, in the late 1990s, free fetal circulating DNA in maternal plasma has enabled the development of noninvasive prenatal tests. Among tests used in current practice, fetal sex determination and RHD genotyping are diagnostic tests based on the detection of sequences usually absent in maternal genome. Noninvasive detection of trisomy 21 is a high-performance screening test based on chromosome counting by next-generation sequencing. These tests contribute to improve the quality of care by reducing the number of invasive fetal sampling and iatrogenic miscarriages, and allowing better targeting of therapeutic treatment. However, their limits should be taken into account, namely the proportion of fetal circulating DNA in plasma (fetal fraction), the trophoblastic origin of fetal DNA, and the possible interference of maternal genome.