| Summary: | 碩士 === 大同大學 === 生物工程學系(所) === 102 === Chromosomal abnormalities may cause lots of diseases; the most common is Down’s syndrome. In recent years, many reports indicated that the incidence of Down’s syndrome is increased by maternal age. As a result, advanced maternal age women ( ≧ 34 y/o) are clinically recommended to undergo amniocentesis. However, studies indicated that, if we use advanced maternal age as a selection criteria for the amniocentesis, only to find about 20% of Down's children, while a majority of 80% of Down's child is born to young pregnant women. Other examinations, such as maternal serum Down screening and nuchal translucency developed for the vulnerability of amniocentesis. But these examinations can only provided the reference of the risk. For them at risk, the amniocentesis is needed to confirm the diagnosis.
In principle, 99% of chromosomal abnormalities can be detected by amniocentesis. Although amniocentesis results in low complication rate and low abortion rate (both ＜ 1％), it is still an invasive testing. Therefore, we require a careful assessment, whether they need amniocentesis or not, for all age of pregnant women.
In order to investigate what indications is the largest group, we analyze all patients (total population 2284) having amniocentesis in hospital since 2005 to 2012.We found that the largest group is advanced maternal aged accounting for 67.69 %, cases at their own expense are 17.73％, maternal serum Down screening are 10.86%, abnormal sonographic finding are 1.05%, neural tube defect or elevated MS-AFP are 1.01% and having risk of trisomy 18 are 0.87%. The major type of chromosomal abnormalities is 「numerical chromosome abnormality」 accounting for 70.83%, which include autosomal chromosome aneuploidies, sex chromosome aneuploidies and mosaicism. And structural abnormalities are 29.17% including deletions, translocation, inversion and duplication.
The results showed that advanced maternal age still has the highest incidence of Down's syndrome and other chromosomal abnormalities. Advanced maternal age have highest sensitivity of ultrasound (16.67%), but not highest detection rate (1.94%). Amniocentesis is suggested to all elder pregnant women. For younger pregnant women who don’t want to have amniocentesis, it is recommended that they had better taking further amniocentesis if they had abnormal sonogram findings.
On the other hand, by amniocentesis and blood karyotyping analysis, we can understand the patterns of chromosomal abnormalities, balanced or unbalanced abnormalities, and whether it will be passed on to the next generation. We can do genetic counseling to avoid occurrence of the disease. Different from other researches, we found that cases at their own expense jump to 17.73% in second place. This shows that parents are not against amniocentesis, when they are worry about babies ’healthy. I hoped my study can give all pregnant women a reference if having amniocentesis or not, and achieve the purpose of early diagnosis and genetic health.
|
|---|
