Before I met the obgyn who took care of me when I was pregnant with Sophia, Christine Yap, all medical practitioners in Singapore whom I spoke to about thalassaemia had very (to my mind) non-progressive views. Their advice to my husband (then fiance) and I ranged from “don’t get married” to “just do amniocentesis to test for thalassaemia”. However, nobody told me about ways that are, to my mind, much better options. I had to research about them and make appointments with a few obgyns to talk through them before I found Christine, who was completely on the same page as me. So today’s post is going to be a rather dry but hopefully informative one.
First, some background. Thalassaemia is basically a genetic disease. As you may know, genes work in pairs. Thalassaemia minor means that one of the gene is the “defective” gene and the other is normal (to put it simply). The fetus will take one gene each from each parent and that forms the fetus’ pair. Probably theory tells us that there is therefore a 25% chance of the fetus being perfectly healthy with a pair of “normal” genes, 50% chance of having one “defective” and one “normal” gene and 25% chance of the fetus having both defective genes. When a person is born with both defective genes, that person has thalassaemia major and is destined to live a short and miserable life. Hence the aim is to prevent that. How then?
Safest choice would be to do pre-implantation testing. Essentially this involves going through an IVF procedure with the fertilised egg being tested to be normal before being implanted. However, this very clinical method of making babies is unappealing to many parents, ourselves included, for obvious reasons.
The next best choice then is, to me, transabdominal chorionic villus sampling (CVS). Essentially the obgyn pokes a needle through the mum’s abdomen to extract a single villi from the mum’s placenta and sends that for genetic testing. Previously it was thought that this method carries a higher risk of miscarriage and fetal deformity. However, more recent research reveals that this is only true if CVS is conducted before 9 weeks of gestation. If it were conducted past 11 weeks, the difference in safety compared to amniocentesis is almost negligible. However, CVS’s very significant advantage is that CVS can be performed at 10-12 weeks wherease amniocentesis can only be safely performed at 16 – 20 weeks. That means with CVS you would know at least 4 full weeks earlier, when abortion is still safe and much less traumatising.
So for the thalassaemia carriers out there (and there are many in asia), I hope this teaser encourages you to find out more about what can be done and not take the word of healthcare professionals at face value. They are only human and have their biases which may or may not be objectively the most correct view.