nuhahyearlyLaunch pricing - Get £50 off!nuhahyearlyCVS is a diagnostic test available from 11 weeks that samples placental tissue to check for chromosomal conditions like Down's syndrome. It gives a definitive answer with results in 3 working days (rapid) or 2 to 3 weeks (full karyotype). The miscarriage risk is similar to amniocentesis at around 0.5 to 1%.
CVS takes a tiny sample of tissue from the placenta, specifically from finger-like projections called chorionic villi. Because the placenta develops from the same fertilised egg as the baby, the cells in the chorionic villi have the same genetic makeup as your baby.
The sample is usually collected through your abdomen using a thin needle guided by ultrasound, similar to amniocentesis. Less commonly, it may be collected through the cervix using a thin tube. Your doctor will decide which approach is best based on the position of your placenta.
The procedure itself takes about 10 minutes, though the full appointment including the ultrasound and preparation is around 30 minutes. Most people describe the sensation as a sharp scratch followed by pressure.
CVS can be performed from 11 weeks of pregnancy onwards, making it available earlier than amniocentesis (which cannot be done until 15 weeks). It is typically offered between 11 and 14 weeks.
You may be offered CVS if your combined screening test or NIPT has returned a higher chance result, if an ultrasound has shown a raised nuchal translucency measurement or other findings that may indicate a genetic condition, if you or your partner are known carriers of a specific genetic condition, or if you have had a previous pregnancy affected by a chromosomal or genetic condition.
Some parents choose CVS specifically because the earlier timing means results are available sooner, which can be important when making decisions about the pregnancy.
Both CVS and amniocentesis are diagnostic tests that analyse your baby's chromosomes. The main differences are timing and what is sampled. CVS can be done from 11 weeks and samples placental tissue. Amniocentesis is available from 15 weeks and samples amniotic fluid. Both have similar accuracy for detecting chromosomal conditions. The miscarriage risk is also similar for both procedures.
Your healthcare team will recommend whichever test is most appropriate based on how far along your pregnancy is and the specific clinical situation.
The risk of miscarriage following CVS is similar to amniocentesis, estimated at around 0.5 to 1% (roughly 1 in 100 to 1 in 200 procedures). As with amniocentesis, this includes the background miscarriage risk at this stage.
There is a small chance that CVS may need to be repeated if the initial sample does not contain enough tissue for analysis. This happens in a small minority of cases.
If you are Rhesus negative, you will be offered an anti-D injection after the procedure.
In very rare cases, the results may show confined placental mosaicism, where the placental cells have a different genetic makeup from the baby. If this is suspected, amniocentesis may be recommended later to confirm the results.
Rest for the remainder of the day after having CVS. Avoid heavy lifting and strenuous activity for a couple of days. Mild cramping is normal. Contact your maternity unit immediately if you experience heavy bleeding, fluid leaking, a high temperature, or severe abdominal pain.
Rapid results (QF-PCR) for the most common trisomies are usually available within 3 working days. A full karyotype analysis of all chromosomes takes around 2 to 3 weeks. If additional genetic testing (such as microarray or exome analysis) is required, timescales will be explained by your genetics team.
The decision to have CVS, like amniocentesis, is personal. The earlier timing can feel like an advantage for some parents who want information as soon as possible. Others may prefer to wait for amniocentesis, or to skip diagnostic testing altogether. All choices are valid, and your healthcare team and ARC (Antenatal Results and Choices) are there to support you without judgement.
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