Prenatal diagnostics

The prenatal (prenatal) diagnostics serves to diagnose hereditary illnesses or being missing formations at the unborn one. The examinations are carried out during the pregnancy. The prenatal diagnostics is remembered principally for women who have.

There is already an increased risk in the following cases which can lead to a being missing formation with the child:
  • if the mother is older than 34 year or/and the father older than 45 year,
  • at charging family case history; hereditary diseases, relative marriages, handicapped brothers and sisters child, add two or more successively restrooms to it,
  • at a German measles infection of the mother in the pregnancy,
  • at an unusual emotional load (handicapped child in the circle of friends or anxious personality structure),
  • if the woman and her partner at the time of the fathering or a nascent mother were exposed to damaging influences. With the father it can be necessary to go back three months before the fathering beginning. The seed cell formation takes place in this time period. An increased dose of radiation, toxic substances or a virus infection as well as the taking of a certain medicine (for example cytostatica, antiepileptica, antikoagulantien) belong to the damaging influences,
  • if have let oneself be seen the ultrasound scans and/or the triple test on-due dates,
  • with alcohol and/or drug addiction.
At the first preventive medical checkup the attending doctor finds out whether the nascent mother for the risk groups belongs. The patient if necessary is referred to humane genetic advice facilities.

About the chances and limits of the prenatal diagnostics one can be advised also with his gynecologist, his midwife, a woman health care center or for the responsible public health department. In the advice conversation the woman and her partner must be informed about the meaningfulness of the triple test. The examinations recommended further perhaps like the thorionzottenbiopsy and the amniocentesis must be explained to the pregnant woman exactly with all risks. The attending doctors have a reconnaissance duty in front of the prenatal diagnostics. In the advice conversation you must discuss also, whether at striking findings a termination of pregnancy is possible for the nascent parents.

Methods of the prenatal diagnostics

Triple test (Mom test)
The Triple test is used to charge the probability at the unborn one for the appearance of a Down's syndrome (mongolism, 3 foldly available chromosome 21) or a so-called neuralpipedeficient (for example open back). The test is carried out approximately between the 15th and 20th pregnancy weeks. The concentration is intended for it by three components out of the blood of the woman. It is the egg-white alphafetoprotein formed by the child, form of the sex hormone Östriol and the pregnancy hormone humane Chroriongonadotropin determined one. There exist the blood findings after a week.

Although the triple test is extremely inaccurate, it serves many doctors as a basis to recommend the pregnant woman an amniocentesis.

The chorionzottenbiopsie
With this method, among other things chromosome damages, certain metabolic disturbances, have muscle diseases (muscle dystrophy, mucoviscidose) and the sex of the child determined for themselves. A statement about neuralpipedeficient (e.g. "open back") cannot be met. This examination is carried out around in specialized centers between the 10th to 12th pregnancy week.

Chorioncotten are components of the placenta (mother cake). The fabric contains the same genetic informations as the body cells of the embryo.

The fabric from the chorioncotten is won with the help of a cannula which is led to the mother cake by the abdominal wall and the uterus wall or by the vagina (sheath) under ultrasound view. The intervention can be itinerantly carried out. Already within 1 to 8 days the result is available. The advantage of this method lies in it that there exist the results relatively in the pregnancy early. In the past, if the question whether a termination of pregnancy shall be carried out arises after this examination, it can as at the fruit water point ion be carried out.

The miscarriage risk after this examination is approximately 0.5 to 2%. The probability that the results are doubtful and a check-up must be carried out is around 2%. The risk of a being missing diagnosis is less than 0.2%.

Fruit water point ion (Amniocentese)
Fruit water point ion is the main started after striking results in the triple test or at the ultrasound. With the Amniocentese chromosome disturbances (for example Down's syndrome), neuralpipedeficient ("open back") and hereditarily conditional muscle and metabolism diseases can be diagnosed. The sex can be certainly. As a rule, the amniocentesis is carried out only as of the 16th pregnancy week.

Under ultrasound control some milliliters of fruit water are taken by the abdominal wall from the pregnant woman with a cannula. The neck place can be deadened locally. Cells of the fetus also taken off are in this liquid. A cell culture is laid out by them. The results of the amniocentesis are available only 2-4 weeks later. Very exact and being missing diagnoses are, however, rare you. The long waiting time up to the arriving of the result is as charging very much felt of many pregnant women.

After the intervention cramps, drifts, fruit water loss or slight bleedings can happen. The being missing birth risk to the amniocentese is 0.5 to 1%. A termination of pregnancy after this examination is a birth induced artificially with drift means. The pregnant woman has usually already built up intensive relations to the unborn one and felt the child movements in this phase of the pregnancy. This late termination of pregnancy can resolve serious depressions with women.

Ultrasound (Sonography)
With this method the pregnancy is monitored (also see the section ultrasound diagnostics in the chapter mother passport) per default. Furthermore the ultrasound can give references to organ illnesses and being missing formations of the child (for example "open back", kidney cysts, cardiac defects). If chromosome disturbances already lead at the unborn one to physically visible changes, then these also can be recognized in the ultrasound (con-way of playing striking neck fold at Down's syndrome).

Ultrasonic waves are sound waves which aren't audible for the human ear. You are thrown back at the examination of the body of the mother and the child and can be made visible over a monitor. The great advantage of this examination method lies in it that it is for mother and child without risk, the pain liberty at the examination and in the immediate availability of the results.

Well no other examination method has made such rapid progress within the last few years. There are two possibilities of carrying out the ultrasound scan. Within the first pregnancy weeks the examination is usually made by a rod-shaped sound head by the sheath after this over the abdominal wall.

Nowadays the ultrasound scan is carried out in almost every gynecological practice. However, the meaningfulness of the ultrasound depends fundamentally on the experience of the attending doctor and the quality of the ultrasonic apparatus. The set up gynecologist can to specialized centers in which a so-called "risk ultrasound" can be carried out transfer the pregnant woman. The transfer is carried out, for example, if the nascent mother belongs to a risk group and says no after incoming advice an amniocentese or amniocentesis.

Dopplersonography
With this examination method the circulation of the umbilical cord and uterus artery, the childlike aorta and an artery of the childlike brain can be measured. On the ultrasonogram this is represented coloredly. With the Dopplersonographie more exact information about the development of the child can be won than for example by measuring the height of the child barely. This special sonography is used in the second pregnancy half at certain risks. Being part of it:
  • Suspicion of a development of the defect of the child,
  • High blood pressure with the mother,
  • dissimilar growth with twins,
  • Suspicion of being missing formations, particularly cardiac defects.
Umbilical cord point ion
The results one umbilical cord point ion give information about infections of the child, rhesus incompatibilities, neuralpipedeficient and changes of the hereditary factors.

As of the 16th pregnancy week the umbilical cord is taken from by the abdominal wall of Mrs childlike Blut. There exists the result after two to four days. The being missing birth risk is 1 to 3%


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