Amnioscopy and amniocentesis
Last reviewed: 23.04.2024
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To study the condition of amniotic fluid, amnioscopy is used, which Saling described in 1962. Amnioscopy is a method of detecting the meconium admixture in the amniotic fluid by visual inspection of the lower pole of the fetal bladder.
The endoscope, equipped with a conical obturator, is inserted into the cervical canal to the lower pole of the fetal bladder. Having removed the obturator, a light source is attached and water is treated through the amniotic membranes, while the amount of anterior waters and the admixture of meconium are determined. A special lighting device has been developed for carrying out endoscopic studies in obstetric practice. The developed device makes it possible to obtain a large and uniform illumination, effective absorption of thermal rays and a large output light. When using the device, you can see abundant front waters, easily shifting, light or slightly opalescent. There are small areas of damp grease and water usually have a milky white color. With a large number of front waters, they have a bluish tinge. Some authors, in fetal hypoxia, distinguish the coloration of waters of the "cloudy" type.
Analysis of amniotic fluid during pregnancy
Analysis of amniotic fluid during pregnancy or amniocentesis is carried out in order to study in detail the chromosome set of the unborn child. If, as a result of previous analyzes, there is a suspicion of a formed chromosomal pathology in the fetus. This analysis is not mandatory, the woman has the right to decide whether to pursue it or not.
It is necessary to carry out the analysis on 15-20 weeks of pregnancy, the safest period is 16-17 weeks. Under the ultrasound control, a puncture is carefully made and a small amount of amniotic fluid is collected. After that the received sample is kept in nutrient solution for several days and studied. The final result can be obtained after 21 days.
Complications after amniocentesis are extremely rare, but there is a degree of risk that you need to know about:
- In 0,5-1% of cases after the analysis can begin labor activity.
- Despite the fact that the procedure is carried out under aseptic conditions, the probability of inflammation exists.
- If a woman has a negative Rhesus, and the fetus is positive, then to prevent the development of antibodies in the mother's body, vaccination is carried out.
Amniocentesis is a method by which aspirates amniotic fluid amniotic fluid. Amniocentesis can enhance the ability to diagnose the condition of the fetus. Based on the study of the amniotic fluid and the cells contained in it, one can determine the genetic risk and prevent the birth of a sick child.
Currently, more than 2500 nosological forms of genetically determined diseases are known. Conducting prenatal diagnosis is justified and expedient in the following cases:
- there is a possibility of having a child with a severe hereditary disease, whose treatment is impossible or ineffective;
- the risk of having a sick child is higher than the risk of complications after applying prenatal diagnostic methods;
- there is an accurate test for prenatal diagnosis, and there is a laboratory equipped with the necessary equipment.
Indications for amniocentesis
The main indications for prenatal diagnosis are:
- presence of structural rearrangement of chromosomes, especially translocations and inversions in one of the parents;
- the age of a woman older than 40 (and according to some researchers, over 35);
- heterozygous condition in both parents in autosom-norecessivnyh diseases or only in the mother with X-linked defects;
- The presence of a parent with a disease with an autosomal dominant type of inheritance;
- the birth of a child with congenital malformations.
Technique of amniocentesis
With transabdominal amniocentesis, the placenta, umbilical cord and fetus can easily be damaged. After careful asepsis and locating the placenta and fetus, choose the place of amniocentesis and under local anesthesia (0.25% solution of novocaine) after emptying the bladder, 4 cm below the navel and 2 cm to the right or left (suprapubic access), amniocentesis is performed. Transvaginal amniocentesis can also be used up to 20 weeks, and after 20 weeks of pregnancy.