The combined screening of the first trimester of pregnancy consists of a prenatal study that determines the risk of the embryo having a chromosomal alteration. To perform this study it is necessary to take a sample of maternal blood where it will be analyzed:
- The placental protein associated with pregnancy: PAPP-A.
- The beta-hCG hormone.
In addition to the analysis of these parameters, the first trimester screening includes an ultrasound to measure the nuchal translucenc