Baby Gender Predictor – Chorionic Villus Sampling (CVS)
Chorionic villus sampling (CVS) is a procedure that can be done during pregnancy to test whether your baby has any chromosomal abnormalities. The test involves taking a sample of part of the placenta called the chorionic villi. During your pregnancy, the placenta is essential as it supplies oxygen and nutrients to your baby, and also removes waste elements from your baby’s blood. The chorionic villi themselves are numerous small and feather-like protrusions and contain the same genetic structure as your baby.
When is chorionic villus sampling done?
A CVS test is normally conducted at around 10 to 13 weeks into a pregnancy when there is a need or desire to check for chromosomal abnormalities that indicate a condition such as Down syndrome or genetic disorders such as Tay-Sachs disease. The analysis of the chromosomes present in cells from the chorionic villi will also indicate your baby’s gender.
How is the CVS procedure done?
An ultrasound is conducted as the first stage of the procedure and this is very important. A full bladder is normally required as this improves the quality of the images produced by an early ultrasound scan. The ultrasound confirms the age and position of your baby, and importantly locates the positioning of the placenta. Based on the positioning of placenta, the doctor shall decide the most appropriate method to take the sample, which will be either a transcervical or a transabdominal entry.
A transcervical chorionic villus sample is taken when your placenta is in low position and the doctor can take the sample through your cervix. Your vagina and cervix will first be cleansed with an antiseptic and then gently opened with a speculum. Your doctor will then insert a thin, hollow tube called a catheter. The catheter is eased upwards until it reaches the placenta. Gentle suction is then used to remove a small sample of tissue.
A transabdominal chorionic villus sample is taken when the placenta is positioned away from the cervix or if you have a cervical infection. First your abdomen is cleansed with an antiseptic. Then, under ultrasound guidance, a long, thin needle is inserted through your abdomen and into the uterus. On reaching the placenta a small sample is extracted using the syringe. Both procedures usually take up to an hour. The majority of this time is taken up with the ultrasound scan and the extraction itself may only be a few minutes.
What will I feel during CVS?
Although the CVS test is an invasive procedure, it is not as painful as it might sound. Before the actual test there will be consultations with your doctor where you and your partner can discuss and ask questions regarding the procedure. During the procedure you will be able to follow the scan on the monitor screen, and patience is advised as this will take some as your doctor makes absolutely sure of the positioning of the baby and placenta. Also you will need to lie still while the sample of tissue is removed. If you are having a transcervical CVS, there is not likely to be any pain as the catheter is inserted, although it may feel intrusive. You may feel some cramping as the actual sample of tissue is removed. If you are having a transabdominal CVS, then there is the option of having a pain-relief injection, however, the actual CVS injection is unlikely to be any more painful than anaesthetic injection. The CVS injection will likely sting a little at first and you may feel some cramping as the needle enters your uterus. The degree of discomfort varies but for most women it is not severe and similar in intensity to mild period pains.
After the test you may feel some further cramping and are advised to rest and avoid any heavy lifting. Some vaginal spotting is also possible, especially if you had a transcervical sample rather than one taken through the abdominal wall. If you continue to feel uncomfortable consult your doctor. It is extremely unlikely that your baby will be harmed during the procedure and your baby will naturally replace the small amount of placenta tissue removed. Nevertheless, know the risks and think carefully before choosing to take the test.
How does the CVS test detect baby gender?
After the sample is taken, the chorionic villi cells are studied which includes microscopic analysis of your baby’s chromosomes. Your baby’s 23rd chromosome pairing will clearly show the gender of your baby. A pairing of XX will mean your baby is a girl, whilst a pairing of XY means you are carrying a boy.
The primary chromosomal analysis shall test for the presence of genetic conditions such as Tay-Sachs disease, haemophilia, sickle cell disease, cystic fibrosis, or thalassemia. Results should be available within one to two weeks depending on the number and types of tests conducted.
How accurate are CVS results?
Chorionic villus sampling is an extremely accurate baby gender predictor with a greater than 99% level of accuracy to identify baby gender, and a similar level of accuracy to identify the presence of chromosomal abnormalities.
What are the risks of CVS?
You should carefully consider the risks of having a CVS test before taking the procedure. Chorionic villus sampling carries several risks of which you should be aware
- Studies suggest that a CVS has approximately a 0.01% risk of causing a miscarriage. Factors that may increase this risk slightly are if the test is transcervical, or if the size of the baby is smaller than what is expected according to its age.
- There is a small risk that the CVS procedure may trigger an infection of the uterus.
- The CVS procedure may cause some of your baby’s blood cells to enter your bloodstream. This is unlikely to be a risk unless you have Rh negative blood. If this is the case you will be provided a drug Rh immunoglobulin after the test which will stop your body from producing antibodies against your baby’s blood cells.
- According some studies CVS testing conducted before the ninth week of pregnancy involve a risk of causing growth abnormalities the baby’s fingers or toes.
Should I have a CVS procedure?
Common reasons for a mother to consider CVS are if you:
- Have had a prenatal screening test with abnormal results
- Have had a previous pregnancy where your baby had chromosomal abnormalities
- Are 35 years old or older.
- Have a history of genetic disorders in your family or your partner’s family
- Also note that chorionic villus sampling does not test for neural tube defects. To test for conditions such as spina bifida, an amniocentesis test is a better option.
Conclusions
A chorionic villus sample procedure is an extremely accurate baby gender predictor. However, remember that identifying your baby’s gender is not the primary purpose of the test. CVS analysis can provide valuable details of your baby’s health which can significantly impact how you act and feel about your pregnancy. The decision to have a CVS procedure should be taken carefully, and you will need to weigh up the advantages of knowing about your baby’s genetic health against the risks of complications. If you are keen to discover your baby’s gender early, and have other independent reasons to take the CVS, such as more pressing concerns regarding your baby’s health, then the procedure is worth considering.
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