(precise diagnosis, organ screening, malformation ultrasound around the 20th – 22nd week of pregnancy)
The advanced ultrasound examination in the 2nd trimester includes the assessment of the timely fetal development, the organ morphology incl. the fetal heart (fetal echocardiography), the amount of amniotic fluid, the morphology and position of the placenta as well as a scan of the maternal and fetal vessels using Doppler ultrasonography. The optimal time for the examination is between the 20th and 23rd week of pregnancy.
Besides heart defects, this precise diagnosis examination allows a number of abnormalities to be diagnosed, e.g. of the spine, kidneys or also the face, which are not yet able to be detected as part of the first trimester screening. Three-dimensional (3D) sonography is also used here. Alongside this, it is possible to carry out a new, individual risk analysis for chromosomal defects taking the first trimester screening into account.
Ruling out a genetic defect with certainty (e.g. Down’s syndrome) is only possible, however, by means of invasive diagnostics (amniocentesis). Alternatively, non-invasive tests (e.g. PraenaTest) have also become available recently, whose indication and limits must be discussed in full with the patient, however.
(late precise diagnosis and follow-up examinations around the 30th week of pregnancy)
The examination in the final trimester is used first and foremost to check the baby’s growth. By determining the amount of amniotic fluid and examining the mother’s and baby’s vessels (Doppler ultrasonography), it is possible to assess the supply to the foetus from the placenta.
In this way, any risk to the child can usually be detected in good time. Particularly in case of abnormalities as part of the second trimester screening, in case of multiple pregnancies, suspected undersupply, reduced amount of amniotic fluid, but also if the baby is suspected of having an infection or blood group incompatibility, examinations are arranged during this period.
Some organ anomalies can also be occasionally detected at this advanced stage of pregnancy (e.g. cardiac septum defects, urinary flow disorders, brain deformities…). By knowing about these defects before the birth, the obstetric and neonatal (paediatric) management can be optimised.