Duru Shah, former president of the Federation of Obstetric and Gynaecological Societies of India and currently on the ethics committee of the International Federation of Gynaecology and Obstetrics, demystifies pre-natal tests, stresses the importance of counselling before these tests, and discusses the Niketa Mehta case in which a woman sought to abort a foetus with cardiac abnormalities after the legally-permissible 20 weeks. Interview by Sameera Khan
What are the pre-natal diagnostic tests available, and what can we learn from them?
First, there are blood tests. For example, the dual marker and triple marker tests look at the level of certain hormones which are ‘markers’ associated with Down’s Syndrome. There is also a test for thalassemia major.
Second, we use ultrasound extensively, four-five times in the pregnancy. Here we look for markers for certain abnormalities. In the case of Down’s Syndrome, for example, certain physical characteristics suggest that the foetus has this condition. With an ultrasound at 18-19 weeks we can pick up lots of information on structural problems.
Finally there are invasive tests. These test the amniotic fluid, chorionic villus tissue or foetal blood. Sometimes we even do a skin biopsy of the baby. The other tests will give you a probable diagnosis -- each one has its own proportion of false positives and false negatives. But when we test the tissue, we are actually looking at the genes, chromosomes, DNA, and this gives us a confirmatory result for certain genetic diseases.
How do you decide that your patient needs a particular pre-natal diagnostic test?
One is the age of the patient. But I do the triple marker blood test on all my patients. The risk of having a baby with Down’s Syndrome is higher as the woman gets older, but that doesn’t mean that a younger woman cannot have such a child. So I offer the test to all my patients who can afford it -- it costs Rs 1,500.
Women aged 40 and above will certainly do it. The main reasons why someone would do a test includes a family history of a particular genetic disease (such as thalassemia or Duchenne’s muscular dystrophy), or a consanguineous marriage, or if one of their siblings has been affected, or if they already have a child with a genetic problem. Also, certain genetic conditions are more commonly found in certain ethnic groups. So if you belong to an ethnic group in which a particular disorder is common, it is virtually mandatory.
There are also pre-implantation diagnostic tests that we do for women undergoing in-vitro fertilisation (IVF) who also have a history of multiple abnormal births. Here I would do an IVF, and once the embryos develop to the eight-cell stage, remove a single cell and do a biopsy to look for specific diseases. This is being done in patients of Duchenne’s muscular dystrophy and cystic fibrosis. It also helps women whose blood is Rh-negative and whose partner is Rh-positive. If the baby is Rh-positive, it can be attacked by the mother’s blood and die. You can do IVF and PGD and transfer only Rh-negative embryos.
Why do gynaecologists offer tests that do not provide a clear diagnosis but only a ‘risk assessment’? Doesn’t this just confuse the patient?
These are screening tests that help you identify high-risk patients with whom you do the invasive tests. But you have to put everything in perspective -- you look at the ultrasound report, the dual marker report, the triple marker report, the foetal ultrasound which is done later, put this together with the patient’s age, whether it is a consanguineous marriage, the family history, and so on -- and accordingly counsel the patient on how much importance you will give to the screening report. If the assessed risk is high, you will definitely offer the invasive test. If the result is borderline, it is less clear. If it is a borderline reading and she is an older woman, and if the ultrasound also gave a borderline reading, I would 100% offer her an amniocentesis test. But if it is a 40-year-old woman for whom a screening test shows low risk, I might tell her: “Don’t worry, the ultrasound looks okay, this test looks okay, that looks fine, you don’t need an invasive procedure.”
You also have to keep in mind the risks attached to doing the invasive test. An invasive test has its own risks.
So the triple marker is to take a decision on whether to undergo an invasive test such as amniocentesis?
Yes, the triple marker is a screening method, not a confirmatory method.
What kind of counselling is done prior to an invasive test like amniocentesis?
We tell the couple why we are doing the amniocentesis, the indications for it, the risks, and explain the procedure in detail.
We also ask them to think about what they will do if the test is positive and there is no treatment for the condition (amniocentesis looks for chromosomal and genetic disorders, for which there is no therapy available). Would they want to continue the pregnancy or terminate it? This you have to discuss with the patient before the procedure. Otherwise, after you get a report and the patient says it is against my belief to do a termination, what is the sense in doing the invasive test? In fact then I’d rather not do the triple marker either. So before you do the triple marker you have to talk to them about all this -- take them to the end of the line and make them see the implications of all the tests.
There are some patients who tell me that they don’t want to do the triple marker because if it finds that the risk is high, and they don’t want an amniocentesis, then they are stressed for the rest of the pregnancy. So they’d rather not know. Whatever the decision, I have counselled the patient beforehand, prepared her for all the possibilities. The patient has to make the final decision.
What if a pregnant woman is unable to make a decision?
If she needs a confirmatory test, I will make it clear to her that in case the test shows a child is affected and I am unable to offer any therapy, then this is what the condition will be and the patient will have to make up her mind about continuing or terminating the pregnancy. If the patient makes it clear in advance that she will under no circumstances abort the pregnancy, I have to think about what I am gaining in doing the test. If I can offer her some sort of therapy, then yes I would do the screening test.
What happened in the Niketa Mehta (2008) case? Why was she subjected to pre-natal tests after the 20th week when Indian law prohibits an MTP except to save the mother’s life?
In the Niketa Mehta case, a foetal 2-D echo, a colour Doppler that picks up any problems within the heart, was used. We do it routinely in patients who are diabetic, have a history of congenital heart disease in the family, or who already have a child with the problem. Or if the ultrasound scan at 18-19 weeks showed some abnormalities. But it can be done only at 23-24 weeks because it is only then that you can see things properly in the heart.
Basically, after 20 weeks we use a lot of ultrasound and colour Doppler tests for certain heart, neurological and kidney problems. These tests are done to know in advance if the baby has a problem so that at birth we can get the baby out quickly, and get in a cardiac surgeon immediately. Parents who have conceived after a long time are very keen to continue. So it does depend on how keen the parents are about that particular child and on continuing the pregnancy.
But in the case of Niketa Mehta, the foetus had too many major heart abnormalities so the chances of the child having a normal, healthy life were very poor.
Currently, medical termination of pregnancy is legal only up to 20 weeks of gestation. You have been quoted as saying the Medical Termination of Pregnancy Act should not focus on the week of gestation but on the health of the foetus as the basis for termination. Could you elaborate on this?
I think the MTP Act should not restrict the termination of pregnancy by any particular week of gestation. They could legalise a cut-off at around 24 weeks. Most cardiac, neurological and kidney-related problems surface by then. But even after that cut-off, MTP could be offered on a case-to-case basis -- if a situation arises that is going to give a poor quality of life to a child, who may have to live from birth with multiple surgeries, and who may never really recover from an abnormality. Every such case should be referred to a committee which would take into account the opinions of an obstetrician, paediatrician, paediatric surgeon, lawyer, maybe a layperson too, perhaps another parent.
Unfortunately in the Niketa Mehta case, the committee sat on the fence and did not make a proper suggestion. I suggest that there be an independent committee at the Centre, not controlled by any medical college or by anyone else, and local committees at the state and city levels with a similar structure. Of course, it’s going to be a big task, but the time has come for us to deal with this.
I happen to be on the ethics committee of FIGO -- International Federation of Gynaecology and Obstetrics -- and we are discussing these very recommendations at the moment. The FIGO guidelines clearly mention that if a child is severely handicapped and this is going to affect the child’s quality of life, then termination at any stage of pregnancy is recommended.
(Sameera Khan is an independent writer and researcher based in Mumbai. She writes on issues related to gender and media)
Infochange News & Features, December 2010