amniocentesis test

amniocentesis
Amniocentesis (not amniocentesis ) can identify and diagnose genetic and chromosomal abnormalities, such as certain chromosomal abnormalities , especially trisomy 21. Amniocentesis is gradually become a routine examination that is increasingly prescribed , then it has some risks that need to know . The number of pregnant women who had amniocentesis has increased fivefold in 20 years in France in 2007 to reach nearly 11 %. Amniocentesis is to perform an amniocentesis using a thin needle through the abdominal wall and uterus . This examination is carried out under continuous ultrasound guidance .
The most common situations

The most common situations in which amniocentesis may be offered are:
family history

The existence of a family history of hereditary disease (some myopathies , cystic fibrosis, etc.). , Malformation or chromosomal abnormalities such as trisomy 21.
The existence of a history of child with chromosomal disorder
A history of multiple miscarriages

toxoplasmosis

When fetal infection is suspected ( toxoplasmose. ..)
Blood

When a blood test performed in the mother shows a suspicion of trisomy 21.
nuchal translucency

When the measurement of nuchal translucency , that is to say, the thickness of the neck of the fetus, made ​​during the first trimester ultrasound is positive ( larger than normal) .
Defects or growth retardation

When one or more defects or growth retardation are detected on ultrasound. Trisomy 21 is not just for older women : all women are affected even if the risk increases with age .
When do?

An age of the mother over 38 years: from that age , the risk of trisomy 21 is 1 in 500 pregnancies from 40 years is 1 in 100 pregnancies
risks

The risks of amniocentesis are exceptional for the mother (less than 1:10,000 ) . There is no impact on the long-term development of the child
The risk of miscarriage within two weeks after amniocentesis , are relatively small, but significant , between 0.50% and 1% for a baby and 3 and 4% for twins.
The risk of infection must be taken into account : according to the French Society of Hospital Hygiene , amniocentesis is a test high risk of infection.

Even carried out in the best possible conditions , amniocentesis causes miscarriage in 0.5 % to 1 % of cases.
HAS recommendations

The National Health Authority wants to reduce by 50% the number of amniocentesis to reduce risks while performing this examination earlier detection of trisomy 21. Indeed, the high number of amniocentesis results in higher numbers of trisomies diagnosed with miscarriage rates .
It recommends new strategies practicing earlier detection of trisomy 21 by measurement of nuchal translucency ultrasound during the third month and a blood sample to assay maternal markers. This method relies on the limitations of these two examinations coupled to specific dates.
It would :
detect 80% of fetuses with trisomy 21
reduce the number of amniocentesis
to achieve an amniocentesis rate of 5 % .

The High Authority for Health also emphasizes the need to control the quality of the examination of nuchal translucency .
A later to screening using the serum marker can be performed during the second trimester in women who could not , for example, benefit from combined screening in the first quarter
The measurement of nuchal translucency , ie the measurement of the thickness of the neck of the fetus, is made in the third month of the first ultrasound at 12 weeks gestation .
The analysis of blood serum markers performed in the second trimester , between 14th and 18 th week of gestation . It reveals the rate of three serum markers : HCG ( hormone secreted by the placenta) , unconjugated estriol and alpha fetal protein , produced by the fetus.

The doctor will decide the exact date of the examination.
Amniocentesis is a test reimbursed by the health insurance fund for women
Aged 38 years or more
Those with a personal or family history of genetic diseases
Those at risk of giving birth to a child with trisomy 21

A change in the rate of blood markers associated with a low recovered during the first scan is an indication nuchal perform amniocentesis .