Amniocentesis
Posted on August 26, 2008
Filed Under pregnancy |
Amniocentesis helps detect and diagnose genetic and chromosomal abnormalities, such as certain chromosomal diseases, especially trisomy 21.
Amniocentesis has become gradually aware that a review is increasingly prescribed, although it has some risks to be known.
The number of pregnant women who had amniocentesis was multiplied by five to 20 years in France in 2007 to reach nearly 11%. Amniocentesis is to make a puncture of amniotic fluid through a thin needle through the abdominal wall and uterus.
This review is carried out under permanent control ultrasound.
The most common situations in which amniocentesis can be offered
An age of the mother more than 38 years: from that age, the risk of trisomy 21 is 1 in 500 pregnancies and from 40 years it is 1 in 100 pregnancies
The existence of a family history of hereditary disease (some muscular dystrophy, cystic fibrosis, etc.) Malformations or chromosomal abnormalities such as trisomy 21.
The existence of a history of child with chromosomal disease
A history of several spontaneous miscarriages
When an infection of the fetus is suspected (toxoplasmose. ..)
When a blood test performed at the mother shows a suspected trisomy 21 and when measuring the nuchal translucency, ie the thickness of the neck of the fetus, made during the first ultrasound quarter is positive (larger than normal).
When one or more defects or stunted are detected by ultrasound.
Trisomy 21 is not only older women: all women are affected even if the risk increases with age.
Well aware of the risks of amniocentesis
The risks of amniocentesis are exceptional for the mother (below 1/10.000)
There is no impact on long-term development of the child
The risk of miscarriage, within two weeks after amniocentesis, are relatively low, but not negligible, between 0.50% and 1% for a baby and 3 and 4% for twins.
The risks of infection are to be taken into account: According to the French Society of hospital hygiene, amniocentesis is a consideration at high risk of infection.
Even done in the best possible conditions, amniocentesis causes miscarriages in 0.5% to 1% of cases.
The recommendations of the high health authority to detect more than 80% of trisomies 21.
The High Authority of Health wishes to decline by 50% the number of amniocenteses to reduce the risks associated with that consideration while making an early screening of trisomy 21.
Indeed, the high number of amniocenteses leads to a rate of miscarriages in excess of the numbers of trisomies diagnosed.
It recommends new strategies by practicing an early screening of trisomy 21 with a measure of the NT during the third month of ultrasound and a blood sample to the level of maternal markers.
This method is based on the combined prescription of these 2 examinations on specific dates.
It would:
detect 80% of fetuses affected by a trisomy 21
reduce the number of amniocenteses
to achieve a rate of 5% amniocentesis.
The High Authority of Health also emphasized the need to control the quality of the examination of the nuchal translucency.
A screening later with the determination of serum markers can be performed during the second quarter among women who were unable, for example, benefit from the combined screening during the first quarter
The measurement of nuchal translucency, ie measuring the thickness of the neck of the fetus, is made during the first ultrasound of the third month at 12 weeks gestation.
The analysis of blood serum markers performed during the second quarter, between 14th and 18 th week of gestation. It reveals the rate of three serum markers: HCG (hormone secreted by the placenta), oestriol non-conjugated and alpha fetal protein, produced by the fetus.
The doctor will decide the exact date of that review.
Amniocentesis is an examination reimbursed by the health insurance fund for women
Aged 38 years or more
Those with antecedants personal or familaix genetic diseases
Those presenting risks to the world a child with trisomy 21
A change in the rate of blood markers associated inferior nuchal translucency found a low during the first ultrasound is an indication to perform amniocentesis.
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