Screening and diagnostic tests are now offered routinely to all pregnant women. This section provides valuable resources about the tests available such as ultrasound, blood tests and information about common abnormalities that may be detected. There are many different tests that can be carried out for a variety of medical conditions, so if you would like clarification please refer to the Flourish glossary, or further information can be found by following the links below.
Maternal Serum Screening Tests in Pregnancy
Two types of maternal screening tests are currently available to women who wish to undergo screening in pregnancy:
Combined first trimester screening - a blood test at ten weeks and an ultrasound at 12 weeks;
Second trimester screening - a blood test between 14-20 weeks.
Fetal Anomaly Ultrasound Scan
It is now routine to perform an ultrasound to check the baby's physical development in all pregnant women at 18-20 weeks. It's important that it is performed by a highly specialised doctor or sonographer using up-to-date equipment. Earlier ultrasound examinations at 8-12 weeks are used to date the pregnancy and when performed at 11.5-13.5 weeks in combination with a blood test are part of second trimester screening.
CVS and Amniocentesis
Chorionic Villus Sampling (CVS) is a test in which a small sample of the chorionic villus or chorion, (the material which lines the uterus that will develop into the placenta), is sampled and tested.
Amniocentesis is a test in which the fluid in the womb (uterus) is sampled and tested. The amniotic fluid that surrounds the baby contains cells shed by the baby as it develops.
Antenatal Ultrasound Abnormalities: Soft Markers
Soft markers identify an increase in fetal risk of genetic disease or malformation. These are findings detected at the 18-20 week scan can occur in a normal fetus and are not automatically considered an abnormality. However, they can be seen more frequently in a fetus with chromosomal problems and so their presence is an indication that a detailed scan should be conducted.
In isolation (not associated with other defects), and in a woman whose screening tests have not revealed any other problems, they are less likely to be of significance.
Antenatal Renal Pelvic Dilatation: Swollen Kidney Tubes
In 1-2 per cent of babies, the area where urine is formed in the kidney,(known as the renal pelvis) and/or the tube that drains urine from the kidney to the bladder (known as the ureter) is dilated. This is detected on the 18-20 week antenatal ultrasound and serial measurements are used to determine the progress of the condition. In most cases this is a normal variation of development and resolves in late pregnancy or shortly after birth. When the dilation does not resolve this may indicate that the tube is blocked or there is reflux of urine up the tube from the bladder. Early detection and treatment is necessary to prevent kidney damage.