By: Michael J. Tucker, Ph.D.
Reproductive Biology Associates, Atlanta, GA
Since its successful inception in 1978, human in vitro fertilization therapy (IVF) has
taken major leaps forward both in terms of success rates and in numbers of couples
treated. In essence, the technology arose to address the problem of blocked Fallopian
tubes, coupling laparoscopic egg collection techniques with improving culture of mammalian
eggs, sperm and embryos. By removing human eggs directly from the ovary, and mixing them
with processed sperm, human embryos could be generated outside of the body in the
laboratory and subsequently transferred to the uterine cavity a day or two later thus
bypassing the tubal blockage. Once established as a relatively feasible technique, new
applications for the technology arose including treatment of endometriosis, adhesions and
anovulation in the female partner, and more recently thanks to sperm injection, many forms
of male factor infertility also.
While conventional IVF really just recreates the natural environment for eggs and sperm
to find each other so that fertilization can occur more or less naturally, sperm injection
techniques (intracytoplasmic sperm injection - ICSI) goes one step further and literally
attempt to force the union between the gametes, consequently overcoming most blocks to
successful fertilization. Once initiated, fertilization is just the beginning of embryonic
development. Sitting in a benign culture environment, the human embryo can reside for up
to five to six days prior to the time when attachment to the uterine wall would need to
start to occur. Therefore, embryos can be monitored in the laboratory throughout this
period if necessary, although most commonly they are replaced in to the uterus on days 2
or 3 of development. Many studies are currently underway to establish optimal culture
conditions for these in vitro embryos including attempts to improve culture medium, or the
use of natural cell cultures from the Fallopian tubes to make the in vitro environment
more "natural". Micromanipulation of the embryos before they are transferred to
the uterus can be carried out not only to enhance the embryos' abilities to implant, but
also to remove individual cells to screen the embryos for chromosomal normality.
Clearly there are limitations as to how much the viability of an individual embryo can
be enhanced, and those of us working in the field of infertility therapy must be mindful
of the limitations of the biological material that we work with. Nevertheless, not to be
too brutally objective about it, the potential of embryos generated from differing couples
according to the nature of their infertilities can vary enormously and relatively
consistently. Age can affect this profoundly, or more specifically, ovarian response. In
those instances where a couple are otherwise fertile save that the female partner does not
possess a functional uterus, and gestational surrogacy is an acceptable option, then,
generally speaking in vitro embryos can be quite easily made. Options such as egg donation
for couples that have non-existent or non-functioning ovaries broaden the choices of
therapy, as too does the use of sperm injection (ICSI) to enable sub-optimal quality
partner's sperm to be used successfully to make embryos. Cryopreservation (freezing) of
any or all embryos generated through the use of IVF is a routinely successful adjunct to
fresh conventional IVF and increases further the flexibility of IVF related gestational
surrogacy therapy.
We at Reproductive Biology Associates occasionally perform compassionate surrogate
procedures utilizing the techniques described above. While we do not arrange for surrogacy
agreements as such, we do provide all currently appropriate and available assisted
reproductive technologies to aid success for couples wanting to carry out gestational
surrogacy.
