New science to improve IVF while fighting gender bias

In what could come as a relief to thousands of women seeking in vitro fertilisation (IVF), Bengaluru-based scientists have come up with a game-changer that will improve the success rate of such procedures, while simultaneously tackling the glaring problem of prenatal gender bias.

The first baby to be born by IVF may have been a girl. However, recent studies conducted by many countries worldwide have shown that babies born via IVF have a skewed sex ratio, resulting in approximately 6% more males. In a nation like India, where the sex ratio is already skewed (943 females per 1000 males), increasing IVF usage is a major concern. However, there is no solution available currently to prevent sex skewing in IVF babies.

The team led by Dr Srimonta Gayen of the Department of Molecular Reproduction, Development and Genetics at the Indian Institute of Science (IISc) explained that IVF-induced impaired dosage compensation of X-chromosome is one of the major factors which leads to the lethality of the female embryos, resulting in lower IVF female babies as well as reduction of the success rate of IVF.

“Dosage compensation” is the scientific term that describes the process of ensuring that the extra “X” chromosome in female mammals is deactivated. In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, however, which is the sex chromosome, differs between males and females. Females have two X chromosomes, while males have one X and one Y chromosome.

The extra chromosome

The research team pointed out that in nature, the second X chromosome is deactivated automatically, but in IVF, this does not happen. “If the extra X chromosome is not deactivated, it can be lethal and the embryo dies,” Dr Gayen said.

It should be noted that how dosage compensation happens in human early embryos was not clear and set the roadblock to having a standard to check the IVF embryos’ quality in terms of proper dosage compensation. Publishing their results in Stem Cell Reports, the team has provided significant insight into the dosage compensation states of early human embryos, which will help develop a new technique to ensure the proper quality of the embryos before implantation.

The research, which is being partly funded by the Infosys Foundation, promises to dramatically increase the percentage of successful IVF procedures and ensure that those female embryos have a better chance of succeeding, on-par with male embryos.

The implications are large. Dr Apurva Satish Amarnath, a fertility consultant at Nova IVF Fertility in Bengaluru clarified that 15% of the general population is infertile. Out of this about 20 to 30% require IVF. “In Bengaluru alone, our three centres get about 3,000 people per year evincing interest in IVF. Out of this, about 50% end up getting the procedure,” she said.

Financial ability plays a factor in the decision of some to opt for the procedure. “The average cost is about Rs 1 lakh,” Apurva said. However, the low success rate means hesitancy in opting for the procedure.

While the breakthrough could help balance the gender playing field in IVF, gynaecologist Dr Sanjeev Kulkarni, pointed out that Indian bias to prenatal gender bias has not changed. “The preference for male over female children is still much the same,” he said.