A leg up for baby making
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- Published 26.05.08
Given a choice, Gita Kapoor, a 37-year-old banker in Bangalore, would have preferred just one child. She and her software engineer husband knew that with their busy work schedules raising even one child wouldn’t be an easy job. Two years ago, they opted for in vitro fertilisation (IVF) at a fertility clinic in their city. Today the Kapoors are proud parents of a pair of chubby twins — a boy and a girl.
It isn’t that the Kapoors are not happy to have more than one child. But they have two children not by choice but because of an inherent shortcoming in the assisted reproduction technique they opted for.
“So far there is no technique available to choose a single, viable embryo for implantation,” says Dr Trichnopoly Chelvaraj Anand Kumar, a veteran andrologist in Bangalore.
As a result, fertility doctors normally implant more than one embryo to increase the chances of pregnancy. “With a single embryo, the success rate of IVF is about 30 to 35 per cent. It goes up to 45 per cent with two embryos,” says Dr Indira Hinduja, who is the first Indian doctor to have produced a test tube baby in India in the 1980s.
There are a number of problems associated with multiple pregnancies. Often, babies born in a multiple birth are premature, have low birth weight and are prone to infections. Also, their mortality rate is slightly on the higher side, notes Dr Hinduja.
But thanks to a team of medical researchers in Australia and Greece, doctors may soon be able to find a way of successfully employing genetic screening to identify embryos that can lead to healthy babies.
In a paper reported in the latest issue of the journal Human Reproduction, the researchers say that DNA fingerprinting, a technique more commonly used in forensic applications and in resolving parenthood controversies, can be a useful tool in fertility clinics. The technique can help pinpoint a handful of genes that can help spot a better embryo that would lead to a successful pregnancy, says Gayle Jones, a researcher at Monash Immunology and Stem Cell Laboratories, Monash University, Australia.
When a couple attends a fertility clinic for IVF, eggs from the woman are fertilised with sperm from the man and the fertilised eggs are allowed to develop in the laboratory until they reach what doctors call the blastocyst phase, or the early stages of embryo formation. This normally takes about five days.
One of the difficult decisions, even for a better-trained fertility expert, is to decide which fertilised egg is to be chosen. With little help from technology to distinguish a viable blastocyst from a non-viable one, they often resort to implanting more than one to increase the chances. This often leads to multiple pregnancy.
But this need not be the case anymore, say researchers at Monash University and the Centre for Human Reproduction at Genesis Athens Hospital in Greece.
For their study, the scientists removed a few cells each from the outermost layer of the resulting blastocysts of 48 women who attended the clinic for IVF treatment.
Of the 48 women, 25 became pregnant, leading to the delivery of 37 babies. Once the babies were born, blood from the umbilical cords or swabs of cheek cells was collected. Subsequently, the scientists used DNA fingerprinting to see which genes were common to the material collected after delivery as well as the blastocyst biopsy.
“By analysing these genes, we have been able to identify those that are key to the processes involved in embryo implantation,” Jones told KnowHow.
Though it is too early, she thinks that they would be in a position to refine the gene set further to a smaller number of genes that are more highly predictive of a viable blastocyst. “The ability to select a single, most viable embryo from a cohort available for transfer will revolutionise the practice of IVF, not only improving pregnancy rates but also eliminating multiple pregnancies and the attendant complications,” Jones said.
The Monash University researchers hope that the technique would be available for clinical use within a couple of years if they achieve further success.
IVF being the most common and cheapest of all assisted reproductive methods in use, such improvements in its success rate will be a boon to a large number of infertile couples, says Dr Kumar.