Chorionic Villus Sampling
This page will give you information about chorionic villus
sampling. If you have any questions, you should ask your GP or
other relevant health professional.
What is chorionic villus sampling?
Chorionic villus sampling (CVS) involves using a needle to
remove some tissue from the placenta. The cells in the placenta are
similar to your baby’s cells. CVS is usually performed between 11
and 13 weeks of pregnancy.
CVS can help find out if your baby has one of the following
problems.
- A chromosome disorder such as Down’s syndrome.
- A genetic or hereditary disease such as cystic fibrosis or
sickle cell anaemia.
However, CVS does not cover all possible problems and the
results may sometimes be wrong. CVS does not show if your baby has
a neural tube defect such as spina bifida.
Figure 1 - Chorionic Villus Sampling
Are there any alternatives to CVS?
An amniocentesis is a procedure that involves using a needle to
remove some of the amniotic fluid that surrounds your baby in your
uterus (womb). However, an amniocentesis can only be performed from
15 weeks.
It is possible to have a detailed scan or a blood test but these
tests can only show if your baby may have a
problem.
What does the procedure involve?
Removing the tissue usually takes less than ten minutes. There
are two ways to perform CVS.
- Transabdominal sampling - Your obstetrician will inject local
anaesthetic into the skin and then place a thin, hollow needle
through your abdominal wall and into the placenta (see figure
1).
- Transcervical sampling - Your obstetrician will place a thin
tube into your vagina, across the cervix and into the
placenta.
What complications can happen?
- Miscarriage
- Discomfort or cramping
- Failed culture
- Uncertain results of your baby’s chromosome pattern
- Infection in the womb
- Premature rupture of your membranes
- Vaginal spotting or bleeding
How soon will I recover?
Your baby’s heartbeat will be monitored for a while using the
ultrasound scan and then you will be able to go home.
You should rest for the next couple of days.
Most results of CVS are normal.
If the results show that there is a problem, your obstetrician
will discuss the options with you.
Summary
CVS is usually a safe and effective way to help find out if
there is a problem with your pregnancy.
Acknowledgements
Author: Mr Andrew Woods MBBS MRCOG FRANZCOG
Illustrations: Hannah Ravenscroft RM
This document is intended for information purposes only and
should not replace advice that your relevant health professional
would give you.
Copyright © 2008 EIDO Healthcare Limited
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