Department of Physiology
All India Institute of Medical Sciences
New Delhi
The field of
contraceptive research and development has undergone a dramatic shift since the
Cairo conference held in 1994 with the onus now to provide adequate reproductive
health care, and to develop woman-centric
agenda towards development of novel approaches for preventing pregnancy
following an unprotected coitus. In
this context the research and development of a once-a-month pill, emergency
contraception and the development of contraceptives agents which can also
protect against sexually transmitted diseases appear to be the need of the hour
as they can be used by a woman depending upon her need and choice.
These contraceptive options target to inhibit ovum implantation so that
interception of pregnancy will occur well within the period of a menstrual
cycle. It is anticipated that the development of once-a-month pill and emergency
contraception will prove to be user-friendly and may also be potentially
user-acceptable. Such methods will
help to reduce the high incidence of mortality and morbidity generally
associated with abortion. In a
developing country like India it is also necessary to provide basic education
and health care information about the available contraceptive options that are
balanced, accurate and intelligible to all likely users.
Indeed, as a reproductive biologist I consider that it is also our duty
to create a movement towards achieving women’s reproductive rights and to
develop strategies in translating such rights into action.
For the development of an effective once-a-month
pill, it is important to understand the physiology of embryo implantation
especially in a primate species. Through
research conducted at the All India Institute of Medical Sciences, studies using
the Rhesus monkey have revealed that a preimplantation embryo signals its
presence to the uterus through the elaboration of embryo-derived secretory
molecules and this process helps to establish endometrial receptivity for
implantation. On the other hand,
receptive stage endometrium also plays a critical role in determining
preimplantation stage embryo growth, differentiation and its viability for
implantation stage embryo growth, differentiation and its viability for
implantation. Thus a new paradigm
of embryo-endometrium dialogue has been established.
The burst of information on the genetic basis of
cellular functions through the Human Genome Project has touched all spheres of
biological and medical sciences. At
the All India Institute of Medical Sciences, the research group in Implantation
Biology is now examining the functional genomics of endometrial receptivity and
attempting to unravel the nature of the critical embryo-endometrium dialogue
necessary for receptivity and implantation, and the potential development of
novel anti-implantation agents for human use.
The research conducted at the All India Institute of
Medical Sciences using the Rhesus monkey model has led to the establishment of
the endocrine basis for blastocyst implantation in the primate.
Through critical embryo-transfer experiments it was established that
post-ovulatory phase ovarian estrogen is not essential for embryo implantation.
Indeed these results closely corroborated later observations from IVF-ET
programmes that successful pregnancies can occur in agonadal women following
embryo transfer with the support of exogenously administered progesterone alone.
It was deemed necessary to define the endocrine requirement for
implantation in the primate since it would then provide the scientific rationale
for developing methods for post-ovulatory stage fertility regulation.
Progesterone was found to be critical for implantation and this led to
the development of an anti-implantation strategy with the focus of preventing
the actions of progesterone in a fecund cycle.
Emergency contraception has been developed to prevent
embryo implantation in cycles in which a woman has experienced unprotected
coitus. Emergency contraception has
been introduced in few developed countries; in India, this method of
contraception is now being launched. However,
as yet researchers are not aware of the mechanisms by which emergency
contraception is achieved. It is
important to understand the cellular basis of the action of a drug, which is to
be taken to prevent pregnancy in a potential fecund cycle.
It is also important to define the extent of the window of applicability
of the drug used for emergency contraception as this has a very practical basis
from the user’s point of view. To
this end research studies have been planned to be conducted at the All India
Institute of Medical Sciences using the Rhesus monkey as an experimental primate
model.
The development of novel contraceptives in the
post-Cairo era must aim towards development of a cafeteria
type of approach with several types of interceptive options being available to
women for her own choice and time of application and for maximal reproductive
health care in state dependent manner. In
this context, research studies towards the timed use of angiostatic molecules as
once-a-month pills are to be conducted by the scientists of the Implantation
Biology group working at the All India Institute of Medical Sciences.
Furthermore, the use of microbicidal drugs as anti-implantation agents
appears promising because they will additionally protect the end users from
sexually transmitted diseases. Research
studies are to be conducted to this end by the scientists of the Implantation
Biology group at the All India Institute of Medical Sciences.
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