Microinjection (Intracytoplasmic Sperm Injection)
Microinjection
(Intracytoplasmic Sperm Injection)
Microinjection is an assisted reproductive method developed for the treatment
of serious male infertility. In case that the sperms are incapable of
fertilizing the ovum, fertilization is aimed at by injecting the sperm
directly into the ovum. In situations that cause serious male infertility,
fertilization with other known therapy methods, including IVF, is either
impossible, or occurs in very low ratios. Sperms defective in terms of
number, motility, and morphology are incapable of fertilizing the ova.
Microinjection is the method of injecting the sperm into the ovum with
the help of mico-pipettes under a microscope. This is forced fertilization
somehow. The procedure is carried out on the heated plate of the microscope
with 200-400 magnifications. Microinjection is carried out for couples
that fertilization cannot be achieved with test-tube-baby method, or for
cases that the number of the ova collected from the female is 5 or less,
as well as serious male infertility. It is possible to carry out the procedure
with very few sperms, and also it is possible to perform microinjection
with sperms obtained from epidydimis or testes when there are no sperms
in semen. No sperms can be found even in the testes in some men. In this
case, cells called spermatids and that are the immature forms of sperms
can be used, if any. However, results of utilization of spermatids are
not very successful yet. Fertilization and pregnancies occur in a low
ratio. The first spermatid applications of our country are started by
our center, and the first spermatid twin pregnancy in the "world
medicine literatue" has been achieved by our center. Microinjection
method has been a revolution in the treatment of infertility, and many
couples who were not given the chance of having babies, were able to have
children with this method. Lecturer Dr. Semra Kahraman et al. performed
the first mixcroinjection application in our country in the year 1994,
and thus led the way. Microinjection was performed with the sperms found
in sperms initially; later the first applications using sperms collected
from epidydimis and testes were performed. First pregnancies terminating
with live births in Turkey were achieved bu using ICSI, TESA, MESA, TESE,
PESA and micro-TESE applications. The first embryo freezing and thawing
procedures and pregnancies and live births of our country were also achieved
in our center. Microinjection procedure is carried out using disposible
and sterile glass micropipettes with deviated tips under microscopes with
special equipment. Ova obtained by ovum colloection procedure are cleared
from cumulus cells surrounding it, and then ova suitable for the process
are determined. A pool containing the special culture medium in which
the sperms will be placed is prepared in the sterile and non-toxic container
that the microinjection procedure will be performed in. Following this,
micro droplets containing special nutrients are prepared for the mature
ova will be placed in. When the sperms and ova are placed in their special
places, a sperm with normal morphology and motile (if any) is selected,
and immobilized by putting the microinjection pipette onto the middle
part of the tail. Then, this sperm is caught from the tail, and it is
moved to the culture media containg the ovum. Sperm is injected into the
ovum by holding it with a special pipette. This procedure is repeated
for all the ova with the same sequence. Following the procedure, ova are
moved to special nutrient media separately. Fertilization control is performed
after 18-20 hours. The numbers of ova that are fertilized and not fertilized
are determined. Fertilized ova and non-fertilized ova are labeled and
placed back to nutrient media; their growth is monitored till transfer
on 3rd, 4th, 5th, or 6th days. The number of sperms must be 20 millions,
progressive motility must be 40%, and normal sperm morphology must be
over 4% in a semen sample with normal characteristics. If the characteristics
of sperms do not meet these conditions, it can be said that male infertility
is present. These parameters are low in serious male infertility, and
these sperms are incapable of fertilizing the ovum. There is not a standard
definition of serious male infertility, however, it can be defined as
being the number of sperms with rapid progressive motility and normal
morphology less than one million. Fertilization may not occur with test-tube-baby
method even if sperms and ova are completely normal. Microinjection method
is applied when fertilization is not possible with test-tube-baby method.
In case of unidentified infertility, fertilization does not occur with
the application of test-tube-baby method with a ratio of 15-20%. Since
there is this possibility of not fertilizing when test-tube-baby method
is applied directly for these couples, microinjection and test-tube-baby
methods are applied simultaneously for couples that number of the ova
are sufficient (10 or more). Ova are thus divided into two groups and
fertilization with test-tube-baby method is checked, and a measure is
taken with microinjection method against a probability of not fertilizing.
Couple must be prepared for microinjection method. At least two semen
samples are obtained from the male partner with 3-4 weeks apart, and he
is evaluated as a candidate for microinjection. In each evaluation, sperms
are exposed to special chemical agents and preparation methods, and their
characteristics are recorded. A sexual fast of 3-5 days approximately
is needed for each evaluation. Urological evaluation is performed on the
male partner. It is determined if additional tests, operations, or drug
therapy will be needed or not. For the female partner, assisting tests
are performed for studying the constitution of reproductive organs and
the response of the ovaries to be expected. Since the sperms are used
that are not capable of fertilizing the ovum in normal way, it is necessary
to investigate any abnormality in the baby in case of a pregnancy. Studies
have shown that the anomaly ratios do not increase in babies born with
this method. However, it has been shown that there is a two-fold increase
in sex-chromosome anomalies. It possible to transfer the genetic disorder
that causes sperm insufficiency in the male to the male infant. An anomaly
in sex chromosomes can cause a sperm production disorder in the male child
in adulthood. Apart from the situation mentioned above, this method causes
no increases in genetic disorders with vital importance. The ratio of
anomalies in babies born in our center after apllying microinjection method
is around 2.7%. This ratio is not different from that of other pregnancies
achieved with normal ways. It is possible to investigate the sex chromosome
anomalies by amniocentesis in the 4th month of pregnancy, especially for
the couples for which serious male infertility is the question. If the
age of the female partner is under 35, amniocentesis is not performed
as mandatory, and the decision is left to the couple. Although there is
such a promising treatment of male infertility available today with ICSI,
the most important factor that determines the success is the age for the
female partner, and the quality of ova. Success in treatment of the male
infertility is still dependent upon female factors because of the increased
chromosomal anomalies in advanced ages. The ratio of chromosomal anomalies
in the ova of the women over 35, and this situation causes difficulties
in implantation of the embryos transferred (holding on the wall of the
uterus), and increases the risk of aborts in case of a pregnancy. In some
other women, fertilization of the ova of insufficient number and of low
quality because of low reserve of ovaries, becomes a problem, and embryos
obtained thus can be of low quality. Freezing the embryos on fertilization
day (pronucleus period) and thus storing them can give successful results.
This can provide a chance for transferring embryos more than once by a
single application. Embryo freezing procedure, which is an economic method
that raises the propability of pregnancy, is applied routinely for suitable
couples. Genetic applications in the period before pregnancy (pre-implantation
period) and the first live birth in Turkey were performed by our center
with co-working of test-tube-baby and genetic centers. Ministry of Health
accepted our center as a Training Center because of our knowledge and
experience accumulation. More than 100 doctors, embryologists, biologists,
technicians, and nurses both from our country and abroad were trained
in our center. Microinjection and test-tube-baby methods are applied for
an average of 80-100 couples each month. There is a risk of abort in pregnancies
achieved with assisted reproductive technologies as well as in normal
pregnancies. Pregnancy ratios diminish dramatically for women over 40.
For women who are over 40 years of age with normal or borderline-normal,
test-tube-baby method is applied by informing them about the low ratio
of success. The upper limit that we accept for treatment is 45.