This study was conducted at the Bangalore Assisted Conception Centre (BACC) – one of country’s best known Assisted Reproduction Technology (ART) centres – by Dr. Kamini Rao, Dr. M.S. Srinivas, and Dr. Anu Kottur. Dr. Kamini Rao is former president of the over 50000–strong Federation of the Obstetrics and Gynaeocological Societies of India (FOGSI) and is also the founder director of BACC. Dr. Srinivas and Dr. Kottur are Dr. Kamini Rao’s colleagues at BACC. The other two authors of the paper are Dr. Partha Majumder and Dr P M Bhargava. Dr. Majumder, who did the statistical analysis, is the Director of the National Institute of Biomedical Genomics in Kalyani, and one of India’s best known human geneticists. Dr. Bhargava, who conceived the idea of this study, is the former and founder Director of Centre for Cellular and Molecular Biology (CCMB) at Hyderabad; he is widely regarded as the architect of modern biology and biotechnology in India and is one of India’s most respected scientists.
When asked what made him conceive the above study, Dr. Bhargava said : “The success rate of clinical pregnancy in women after in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) in the first three attempts, with two to three embryos transferred, has been reported to range from 25 to 33%. Further, this success rate seems to be identical with that obtained in women in natural cycles, when the couple does not suffer from any known form of infertility and the intercourse takes place at the right time. While seeking an explanation of the above phenomenon, we recalled the observation of Hilda Bruce, followed by others, during 1959-1968, that if, 24 hours after mating, a mouse belonging to a different strain than the stud mouse was placed in the cage of the female mouse, partitioned in such a way that no physical contact of the non-stud male with the female was possible, pregnancy was blocked. It, therefore, seemed possible that the above-mentioned low percentage of successful pregnancies in the human species, may be due to the exposure of the woman, after IVF, ICSI or sexual intercourse, without physical contact, to men other than the male partner. We, therefore, isolated randomly selected 729 women from all other men except the husband for three full days after embryo transfer following IVF/ICSI, and followed them to the end of pregnancy; 1005 randomly selected women who were treated similarly but not isolated, served as the control group. Isolation was done either in a room in BACC, or at the home of the woman. The establishment of clinical pregnancy as well as live births were more than 50% higher in the isolated group than in the control”.
When asked about the exact mechanism of the above phenomenon, Dr. Bhargava and Dr. Kamini Rao said that it was still not fully understood. In the case of mice, the existing evidence strongly indicated that the genetically determined individual–specific smell of the non-stud male mouse led to reduction in implantation of the eggs after fertilization by the sperm of the stud male. The same phenomena may be occurring in the case of humans, implying that there may be an olfactory block to implantation of the fertilized egg in the human species as well. This may explain why even when both the man and woman are fertile and the intercourse takes place at the right time, pregnancy seems to be established only in about 30% of the cases as, in most cases, the woman is probably exposed to the smell of men other than the one with whom she had the intercourse, during the three days after the intercourse that are required for implantation of the fertilized egg on to the wall of the uterus.
It, therefore, appears that the chances of establishment of clinical pregnancy in a normal fertile woman, may depend, besides the known factors such as age (and the number of embryos transferred in the case of IVF/ICSI), on two hitherto unrecognised factors: (a) olfactory compatibility of the woman with the male partner, which may be determined genetically; and (b) the extent to which the woman is protected from the smell of all other men [except, probably, the identical twin of the male partner, remembering that a dog cannot distinguish between identical twins (Prof. Colin Blakemore, FRS, of Oxford University, demonstrated this on BBC television in December 1982)] during the period required for implantation.
Dr. Bhargava and Dr. Kamini Rao have, in the above-mentioned paper, suggested further studies to confirm and understand the molecular mechanism of the olfactory block to implantation that their studies suggest. Sourced From: Mediacom PR
