In Vitro Fertilization (IVF)
In vitro fertilization refers to the process of achieving
fertilization between the sperm and ovum in the laboratory under
artificial conditions, and placement of the dividing zygote into the
uterus of the mother.
The number of babies conceived worldwide
by in vitro fertilization is increasing day by day, with millions and
millions of infertile couples benefiting from the treatment option. It
would not be exaggeration if IVF were called “ A Boon to the Medical
Field” because the technique has been a dream come true for parents
longing for a child.
Of the various treatment options available for the treatment of
infertility, none of the treatment procedures have had an impact on the
society as much as in vitro fertilization. The use of these reproductive
techniques has generated tremendous interest, concern and controversy
in the recent years.
Human beings practice sexual reproduction, which involves the fusion of the sperm and ovum.
Sperm
is the male gamete and a male probably makes and releases several
trillion sperms during his lifetime. Sperm production does not begin
until puberty. However it continues till the rest of life although the
quality may be compromised with increasing age. The sperm is very small
compared to the human egg and is made up of three major parts, the head,
neck and the tail. The total length of the sperm is about 0.06 mm in
human beings. The human sperm takes only about 3 months to mature and
can be released instantaneously. So the sperm, which is ejaculated
today, was manufactured 3 months ago!
The egg on the other hand,
is already present within the female, although immature soon after
birth. At the time of puberty, one of the eggs mature to be released by a
process called as ‘ovulation’. The egg is roughly 5 times the size of
an average sized cell in the human body. Ovulated at the rate of one egg
per month for the next 35 to 40 years between puberty and menopause,
these eggs will not be completely mature unless and until fertilized
with a sperm.
One ejaculate from a fertile male contains at
least 250 million sperm that is released into the female reproductive
tract. These million sperms are swept to the fertilization site mainly
by rhythmic contractions of the female reproductive tract and by
swimming process. Out of the sperms attempting to fertilize the oocyte,
only one sperm wins the battle against a million others. Certain
chemical and electrical process initiated in the egg ensures that other
sperms don’t fertilize with the oocyte. This is a remarkable mechanism
conferred by Mother Nature to keep the population under control.
Fertilization
is a sequence of events that begins with contact between a spermatozoon
and an oocyte, leading to their fusion, which leads to the formation of
a zygote and ends with the initiation of its cleavage.
With the
union of egg and the sperm, another life begins. This new cell, now
called as the zygote, immediately divides into two, then into 4, 8, 16
and so on. This happens a number of times giving rise to tissues, organs
and organ systems and ultimately gives rise to a marvelously complex
newborn of more than a trillion cells in just 38 weeks.
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