Prenatal Diagnosis
Prenatal diagnosis aims to detect and, if possible, treat many embryo and fetal pathologies at an early stage.
MAIN AIMS OF PRENATAL DIAGNOSIS:
• reassure and reduce anxiety experienced by all couples during pregnancy, and particularly by those at high risk for congenital disorders;
• provide detailed and specific information to couples at risk for congenital disorders;
• inform couples at risk for a particular disease on whether there is a specific test able to diagnose that anomaly;
• start a pharmacological and/or surgical treatment on a fetus with a disease;
• improves medical, psychological and postnatal behaviour if a fetal anomaly is diagnosed.
INDICATIONS FOR PRENATAL DIAGNOSIS:
• advanced maternal age
• a child with chromosome pathology
• family history of chromosome pathology
• family history of genetic disorder
• family history of neural tube defects (such as spina bifida)
• family history of other congenital anomalies
• fetus anomalies detected during the current pregnancy (with the scan)
• other high risk situations: consanguinity, miscarriage (frequent/repeated abortion, intrauterine fetal death), maternal pathologies.
In some cases the advice of a medical geneticist is recommended.
Common prenatal diagnosis methods can be “non invasive“ or “invasive”.
NON-INVASIVE PRENATAL TESTS
ULTRASOUND SCAN: detects a large number of congenital anomalies present in a fetus.
MAGNETIC NUCLEAR RESONANCE: extremely promising technique for studying the fetus brain, liver and face that can be used to complete an ultrasound scan.
COMBINED SCREENING TEST (First Trimester Screening – 11 weeks + 0 days until 13 weeks + 6 days): maternal age risk combined with an ultrasound evaluation of the fetus (Nuchal Translucency) and maternal blood screening test (free ß-hCG and Pregnancy Associated Plasma Protein).
With a false-positive rate of 5%, it detects 90% of Down Syndromes and 80-90% of other chromosomal abnormalities (Trisomy 13 and 18).
TRIPLE-TEST (Second Trimester screening – from week 15 to 18): maternal age risk combined with maternal blood screening (a-Fetoproteina, hCG and non conjugated estriol).
With a false-positive rate of 5%, it detects 65% of Down Syndromes, and 95% of neural tube defects (spina bifida).
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Villocentesi Amniocentesi
Team Standing prenatal diagnosis:
Prof. Dandolo Gramellini - Specialist in Obstetrics and Gynecology, Pathology Specialist in Human Reproduction;
Dr. Tommaso Rossi - Specialist in Gynecology and Obstetrics, operator accredited by the Fetal Medicine Foundation in London;
Dr. Maria Cristina Pattonieri - Specialist in Pathology and Laboratory Techniques;
Dr. Chiara Fecci - Biotechnology
Fetal Medicine Centre
INVASIVE PRENATAL TESTS
Chorionic Villus Sampling (CVS): the test is performed under continuous ultrasound guidance. An 18-20 Gauge needle is inserted through the abdomen to collect a small sample of chorionic villi from the placenta. These cells will then be analysed for genetic abnormalities. The test can be done after 10 weeks of pregnancy; it is an outpatient procedure and no anaesthesia is needed. Preliminary test results are usually available in 7 days (direct analysis method); final test results are available in about 20 days (cultural method).
AMNIOCENTESIS:Under ultrasound guidance, a 20-22 Gauge needle is inserted through the abdominal wall and uterus into the amniotic sac in order to obtain a sample of amniotic fluid that will be analysed. The test can be performed after 15 weeks of pregnancy;
it is an outpatient procedure and no anaesthesia is needed. Preliminary test results are available in 3 days (QF-PCR); final test results are available in about 20 days (cultural analysis method).
Invasive diagnostic procedures such as amniocentesis or CVS, is arranged after a preliminary ultrasound scan to determine the exact gestational age and whether the exam is feasible or not.
A few days after the exam another ultrasound check is performed. Ultrasound scans before and after the procedure, as well as other genetic investigations required after test results do not involve any additional cost for the patient.
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