The aim is to identify those pregnancies with a high risk of foetal congenital defects.
First trimester combined screening test for chromosome disorders: This is not a diagnostic test. It simply provides a statistical assessment of the risk of having this type of disorder. Two biochemical parameters are measured in the mother’s blood, which associated to the ultrasound nuchal translucency measurement, will provide a risk index. If the risk estimate is high, the pregnant woman can decide, taking into account risks and benefits, whether she wants a diagnostic test, called amniocentesis to be performed.
Neural tube defect serological screening test: Second semester biochemical screening to determine AFP and β-HCG. An increase or decrease in these proteins can indicate a chromosome disorder. If the risk is high, there is the possibility of performing an amniocentesis.
Morphological ultrasound scan at 19-20 gestational weeks. This is important in order to detect pregnancies with a high risk of chromosome disorders, and particularly for diagnosing major and minor foetal defects. If there is a high risk of chromosome disorders, there is the possibility of performing an amniocentesis.
Amniocentesis: is an invasive procedure which involves taking 15-20 cc of amniotic fluid through the transabdominal puncture and suction of the amniotic cavity, from the 15th gestational week. The chromosomes most frequently involved in chromosome disorders suffered by newborns are analysed.
4-D ultrasound scan: This has no diagnostic value, but it gives a moving image of the baby before birth.