1) Amniocentesis – Removal of fluid from the baby
Between 2% and 4% of babies are born with various anomalies. Genetic defects have a significant effect on their occurrence. Since there is currently no permanent treatment for genetic diseases, early diagnosis of these diseases and, if the mother and father decide, termination of pregnancy before the baby reaches the "critical" limit (for example; Down syndrome) is very important for the health of the mother and the baby. For this reason, there are many different methods used. Among the prenatal (before birth) diagnostic methods that require invasive procedures in the mother, the most commonly used method is amniocentesis.
Amniocentesis is mostly used for definitive diagnosis in cases where older mothers-to-be examine their babies for chromosomal anomalies and in cases where complications are seen in one of the triple test, double test or quadruple test examinations.
2) What is amniocentesis?
Amniocentesis (AM) is the name given to the process of entering the uterus with a needle through the skin of the expectant mother's abdomen and from there reaching the amniotic fluid in which the baby swims and taking fluid from this area. AS can be applied for treatment purposes in cases such as severe polyhydramnios, i.e. the baby's fluid being more than it should be, to relax the expectant mother, or for diagnostic purposes such as examining the baby for chromosomal anomalies, searching for NTD (neural tube defects) or examining the baby's lung development.
3) In what cases is it applied?
Today, amniocentesis is mostly applied to expectant mothers for diagnostic purposes. With these applications, cytogenetic diagnosis, i.e. chromosome anomaly research, whether the baby has metabolic diseases, diagnosis of neural tube defects in the baby (measurement of alphafetoprotein in amniotic fluid and acetylcholinesterase when deemed necessary), determination of the degree of the baby's effect in case of blood group incompatibility (measurement of a substance called delta OD450 in the fluid), determination of whether the baby's lungs are developing (determination of the L/S (Lecithin/Sphingomyelin) ratio or PG (phosphatidylglycerol) ratio in amniotic fluid) and many other conditions can be diagnosed. With the development of genetics, today, not only certain chromosome anomalies in babies but also diseases caused by single gene defects can be diagnosed. The number of single gene diseases that can be recognized is also increasing.
4) When is amniocentesis performed?
The only technical difference between the treatments performed for treatment purposes is that they can be performed at any stage of pregnancy.
Amniocentesis, which is used for diagnosis, can usually be performed from the 16th week onwards.
5) How is amniocentesis performed?
After a detailed ultrasound is performed on the expectant mother and the baby's intrauterine map is determined, the abdominal skin is wiped with an antiseptic substance. Along with the ultrasound, a needle of a suitable thickness for the procedure (usually the needles used in spinal anesthesia are used in the treatment) is inserted into the uterus from a suitable area of the abdomen and from there it is brought to the uterine cavity where the amniotic fluid is located. With the help of the syringe, the first 0.5 milliliters of the amniotic fluid drawn is thrown back and a sufficient amount of fluid is drawn again. After another ultrasound examination, the needle is removed and the procedure is completed. This amniotic fluid material taken from the mother's abdomen is delivered to the laboratory at room temperature.
In genetic amniocentesis, on average, around 20 milliliters of fluid is taken. (i.e. up to 30cc). This rate is equal to 10% of the total amniotic fluid amount of a baby in the 16th week of pregnancy. It is estimated that the baby completely replaces this fluid within 3 hours.
6) What are the risks of AS?
Since the needle pierces the amniotic membrane, there is a risk of 1 in 400 losing the baby due to miscarriage. Various contractions may occur in the uterus after the procedure. Therefore, the expectant mother should not get up immediately and should rest. After the amniocentesis procedure, amniotic fluid may come from below (1% chance). In such a case, you should definitely inform your doctor. With follow-up, the fluid may stop coming and the pregnancy can progress smoothly. Fever may occur as a result of the fluid getting infected inside the uterus. If fever occurs, shivering, or foul-smelling discharge occurs, you should immediately inform your doctor.
As a result of the fluid taken, it does not cause any problems for the baby.
The possibility of the baby being injured as a result of contact with the needle is very, very low.
7) How are AS results reported?
After the application of aminosynthesis, it states that the baby's chromosomes are normal in the laboratory environment (it is still forbidden to declare gender in this report in our country). This report, which comes as "normal", cannot show whether the baby has structural and congenital anomalies, minimal chromosome errors such as microdeletion and microduplication, and diseases such as fragile X syndrome that require special techniques.
If the FISH (fluorescence in situ hybridization) method is used, the result will be available within 1 day on average. However, since the FISH result is not 100%, a period of 12 to 22 days is required for the final result to arrive. If a chromosomal abnormality is detected in the baby, the laboratory prepares a report stating this situation (such as Trisomy 21 (Down syndrome); 45 X0-Turner syndrome).
8) Are AS results safe?
The probability of a chromosome analysis with a normal result being incorrect is very low.
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