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常见问题:绒毛膜绒毛取样
像羊膜穿刺术, chorionic villus sampling (CVS) can detect significant chromosomal differences, 比如那些导致唐氏综合症的基因, as well as extra or missing pieces of chromosomes, some of which are associated with certain conditions. CVS can also be used in at-risk pregnancies to diagnose some conditions caused by a difference in a single gene, such as cystic fibrosis and Tay-Sachs disease.
十大赌博平台排行榜, nurses and other members of the UCSF产前诊断中心 bring a wealth of expertise and experience to your care. They have performed more than 17,000 CVS procedures over the past 25 years.
A major advantage of CVS is that it’s performed much earlier in pregnancy, at 10 to 13 weeks (compared with 16 to 22 weeks for 羊膜穿刺术). This allows you more decision-making time, if needed, and an earlier start to any treatment.
A disadvantage of CVS is that it can’t detect neural tube defects, such as spina bifida. 然而, these conditions may be screened for later in the pregnancy with an ultrasound exam plus the alpha-fetoprotein test, which uses a blood sample from the pregnant person.
What happens before and during the procedure?
首先你要见一位基因顾问, who will assess your pregnancy history and family history, explain options for prenatal screening and testing, and answer any questions or concerns you have. This appointment takes about two hours and can happen in person at the UCSF产前诊断中心 或者通过视频访问.
Then you’ll have an ultrasound to assess the location of the placenta and the gestational age of the pregnancy. The CVS procedure is performed under ultrasound guidance and takes about 10 minutes. It involves removing a tiny piece of tissue from the placenta, either by inserting a needle through the abdomen or inserting a catheter (a thin, 柔性管)通过子宫颈. Most patients don’t find the procedure painful, but some experience cramping or other minor discomfort.
样品被送到实验室进行测试. Most results are available within two weeks, although certain tests may take up to a month.
There is a small risk of miscarriage as a result of CVS. 大约是450分之一.
A positive result means the test found a genetic abnormality. 如果发生这种情况, you’ll be able to discuss the finding and your options with an obstetrical geneticist and a genetic counselor from our center, 还有你自己的十大赌博平台排行榜. For any decision you make, we offer referrals and resources for support.
Most insurance plans cover CVS and other prenatal tests, especially if you're 35 or older. You may need a referral from your primary care doctor or an authorization from your health plan to ensure coverage. Our office staff is available to help with insurance questions.
加州大学旧金山分校健康 medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.