Prenatal genetic Counselling

Prenatal Genetic Counselling

In my practice, I place great importance in counselling for testing of specific genetic disorders. Whilst it can be performed in pregnancy, I believe the real value lies in testing in the pre pregnancy period.

There are 2 scenarios:

A couple has a known history in themselves or in the family of a genetic condition
Should this be present, it may be possible to assess the risk of the couple having a baby who could be similarly affected. However, this may take a long time as information may be required to be obtained from family members. Sometimes other members of the family may need to be tested. Thus it will be important to undertake such assessment well before you plan for pregnancy.
Screening to check if a couple are carriers for genetic conditions
With the knowledge obtained from the knowledge of the human genome, numerous tests are now available for screening a couple’s risk of having a genetic condition that may be passed onto the baby. Whilst some factors like race may increase the risk of specific genetic disorders, many will not have any indication or family history.In all cases, the couple does not have any symptoms of this but may carry the gene.
If only one partner carries the gene (the other being a non carrier) then the baby at worst will end up being a carrier and have no symptoms. If both couples carry the gene, then the baby will have a significant risk that it may be affected. If this was the situation for the couple, then this would allow them to plan appropriately for the pregnancy.
Examples of genetic disorders tested for include cystic fibrosis, fragile X, spinal muscular atrophy, thalssaemia, biotinidase deficiency, Tay Sachs and Gauchers Syndrome to name a few.

Why undertake such screening?

The advantage of pre pregnancy testing is so that couples who are both carriers and thus at higher risk of having an affected baby, can plan for their pregnancy. They may

despite their risk, choose to get pregnant and then be tested in pregnancy. If their baby is then affected, then they may have to consider abortion

consider IVF and then test the embryo. Only unaffected embryos will be implanted, thus avoiding the need for considering abortion in the pregnancy.

The advantage of being able to use IVF for embryo testing in affected couples should not be under estimated. It avoids the difficulties of testing during pregnancy and the possibility of needing to make heart wrenching decisions on abortion.

Furthermore, such knowledge can be disseminated to other members of the family to allow them the option of screening to help them in their pregnancy. The couple’s child can also be tested later in life to determine if they carry the gene which will be important in turn for them to plan for their own lives.

It is important to understand that screening is not for everyone. There are implications in undertaking such screens. The decision to do so will need to take into account a couple’s philosophy and beliefs. I can assist in this decision making and advising on the myriad of tests available.