Prenatal tests are a number of tests performed prior to and at the time of pregnancy, in order to assure maternal and fetal safety, as well as to ensure that the pregnancy will lead to normal delivery.
Aim of prenatal control
The aim is to detect factors that may potentially threaten the pregnancy or the delivery.
Prenatal screening tests are performed both on the parents and the fetus and include:
- Blood tests
- Blood analysis
- Rhesus status
- Haemoglobin electrophoresis
- Australian antigen
- Red & CMV antigens (IgG & IgM)
- RPR (only on people who may have come in contact with syphilis)
- Antibodies for toxoplasmosis
- Blood glucose
- Urea
- Creatine
- Transaminase
- HIV
- Urinalysis
- Gynaecological exams
- Pap test
- Culture of vaginal discharge for ureaplasma, mycoplasma, and chlamydia
- Transvaginal ultrasound screening of the genitals
- Mammogram if one is required after a breast exam
- Ultrasounds
- 1st trimester (nuchal translucency and PAPP A)
- 2nd trimester
- 3rd trimester
- Cardiotocography during the third trimester
- Diagnostic methods for chromosome abnormalities
- Trophoblast
- Amniocentesis
- Oral glucose tolerance test
Prenatal testing- 1st trimester
Prenatal screening in the first trimester aims at detecting any chromosomal abnormalities, such as trisomy (type 13, 18 and 21) and Down syndrome.
An ultrasound, the woman’s age and levels of the serum marker PAPP-A and hCG help to detect over 90% of fetuses with trisomy.
Prenatal testing- 2nd trimester
At this stage we can perform a B-mode ultrasound, which will provide essential information about the development of the fetus, about the placenta, the umbilical cord and blood supply in the uterus. It can also detect a considerable number of fetuses with Down syndrome that were not detected in the first trimester.
In case an ultrasound or biochemical marker screening show any chromosomal abnormalities, an amniocentesis is recommended.
A sample of amniotic fluid is extracted without anaesthesia and allows for the discernment of fetal karyotype.