During pregnancy, for a variety of reasons, a fetal condition may occur. The child is surrounded by amniotic fluid - an amniotic fluid that contains living cells of his skin and other substances.
Their research helps to find out valuable information about the health of the fetus, but called this diagnostic method - amniocentesis. What is amniocentesis?
Amniocentesis is a method of studying amniotic fluid. It is a puncture of the abdominal wall of the uterus. During its conduct, a small amount of amniotic fluid is selected and a number of studies are conducted: hormonal (the number, composition of hormones), immunological (detection of violations in separate parts of immunity), biochemical (composition of the amniotic fluid). The combined analysis of these fluid studies helps determine the general condition of the fetus and to determine the degree of risk of genetic anomalies.
There are several hundred varieties of genetic defects that can reveal the method of amniocentesis, including chromosomal diseases (Edwards, Patau and Down syndromes), neural tube defects (spinal hernia, etc.). However, such congenital defects, such as the wolf's mouth and the affection of the lip, do not show amniocentesis.
Indications for the study
A decision on the use of the method of amniocentesis may only be taken by a pregnant woman, as this procedure involves certain risks. And thoughts about the expediency of this study diverge. First of all, you need to be prepared to ensure that in case of anomaly detection, you may have to stop pregnancy. Nevertheless, timely detection of a defect in a child will give time to find out what kind of help may be needed.
And since amniocentesis presents some danger to the health of the mother and her baby, this test is offered only to women who have strong preconditions for the development of a fetus of genetic diseases, including in cases where:
- An ultrasound examination revealed a serious problem, such as a heart defect that may indicate chromosomal abnormalities;
- According to the results of screening tests there is a risk of infant birth with chromosomal abnormalities;
- One or more relatives of a woman and/or father of a child have some genetic abnormalities;
- A pregnant woman is over 35 years old, since the risk of having a sick child increases from this age - 1 case is approximately 300 (for comparison, at the age of 20 years old this ratio is 1 to 2000).
- The woman already had a pregnancy with genetic anomalies in the fetus.
The term and method of conducting
Apply the method of amniocentesis during the period of pregnancy 16 - 18 weeks (that is, 14 weeks after the first day of the first menstruation, which did not occur). However, if a physician has reason to suspect a fetal development of a heart defect or a serious genetic disorder, then amniocentesis is allowed for up to 14 weeks. Also, in some individual cases, amniocentesis is carried out and in later cases for the purpose of artificial interruption of pregnancy, if there are medical indications. In this case, a concentrated solution of salt or other preparation is introduced into the bubble. Carries out this diagnostic test obstetrician-gynecologist in the operating room.
Before the pregnancy is done, the ultrasound is necessary to determine the location of the placenta to avoid damage to the puncture. The puncture itself is made through the anterior abdominal wall of the uterus, preliminary treating a small area of the skin of the abdomen with a five percent alcoholic solution of iodine. The puncture site is inhaled by local anesthesia to reduce discomfort. Under the control of an ultrasound, the doctor inserts a thin, long hollow needle into an amniotic cavity and collects 15-20 ml of fluid, which is sent to a laboratory analysis.
The laboratory counts all the chromosomes and defines their structure, but the procedure lasts two to three weeks. The fact is that for diagnostic purposes, a certain number of baby cells are needed that are grown under special conditions, which is why the results are not immediately received by a woman. Immediately after amniocentesis, the patient may experience pain in the abdomen. In some post-amniocentesis, minor spotting is observed. Therefore, as a rule, the doctor recommends bed rest during the day.
Also, after amniocentesis, for some time, the doctor will check the baby's heartbeat and observe a woman to prevent possible uterine contractions.
Contraindications to amniocentesis - presence in the uterus of a benign tumor; Uterine developmental defects; Location of the placenta on the anterior wall of the uterus; The threat of abortion; Infectious processes or fever status.
Consequences of amniocentesis
The conduct of this study involves some risks.
Possible consequences of amniocentesis:
- Development of an infection or other complications (in one of 200 women);
- Bleeding in a woman or fetus;
- The feeling of taking over a few hours after the procedure - the most common effects of amniocentesis;
- Miscarriage of a healthy child (1 case out of 500);
- Spontaneous abortion
- Mothers who have a negative Rh factor before the procedure, in order to protect the baby from its antibodies, are injected with Rho-gamma globulin. In 2 of 100 cases, this precaution provokes a miscarriage;
- Injury of the fetus (the probability of such an effect of amniocentesis is practically zero, but nevertheless, it is possible, if the doctor will touch the vital area of the child with a needle);
- Damage to the bladder, which leads to bleeding and the end of amniotic fluid (the patient should lie on preservation, treatment can be delayed for several months);
- Preterm labor.
Taking into account all the above, each woman must take into account the possible consequences of amniocentesis and weigh all pros and cons against the test before accepting it. In addition, the test result still can not guarantee the birth of a completely healthy child, it only excludes some pathologies.
Its accuracy is about 99.4%. Therefore, each pregnant should consult a geneticist and then make the final decision.