Whatis Biology Good For?
Helping A New Life Begin: In Vitro Fertilization
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In vitro fertilization (IVF)is a
fertility procedure first succeeded in 1978 by the late British
gynecologist Dr. Patrick Steptoe and his co-researcher,
embryologist Robert Edwards. Since then, the procedure has been
further developed and fertilization outside the human body is now
available throughout the Western world. In fact, more than 300
centers in North America alone practice IVF and over 40,000
babies worldwide have been born after IVF.[Image]
What is in IVF?
Simply stated, IVF involves removing eggs from
a woman, fertilizing them in the laboratory culture dish (the
name "test-tube baby" is actually a misnomer)
and then transferring the fertilized eggs - now called
"zygotes" - into the uterus a few days later.
Ultrasound of Follicles
Egg with two pronuclei
Eight cell Pre-embryo
Preparation for IVF:
Hormones injections of Lupron, Metrodin,
Pergonal or Humegon allow the ovaries to develop many
follicles, inducing the woman to 'super ovulate', and
increasing the number of egg-containing follicles
Several follicles are stimulated to
develop at the same time so that a group of eggs will be
available for fertilization.
Tests and ultrasounds regulate the woman's
cycle to determine the optimal time for follicle / egg
Using an ultrasound-guided needle placed
through the vagina, the doctor retrieves follicular fluid
/ eggs from the follicles.
This procedure requires neither
hospitalization nor general anesthesia. (Local anesthesia
and/or mild analgesics may be taken to alleviate any
The eggs are immediately identified by an
embryologist, and then placed in an incubator.
After a short rest, the women returns home
and can resume normal activity.
When ready for fertilization, about 50,000
to 100,000 of the most motile sperm are incubated with
each of the woman's eggs.
Or, to increase the rate of fertilization,
a fertility doctor may perform Inter Cytoplasmic Sperm
Injection (ICSI), which is direct insemination of a
single sperm into the egg. [Image]
If more than four eggs are retrieved, all
eggs are fertilized and the extra embryos may be frozen
for future use. If freezing is not available or desired,
the eggs may be donated to another infertile couple or to
the IVF center, which would then use them for refining
culture methods and techniques.
The four basic steps to
1. Egg's metabolism must be turned on.
2. One sperm must penetrate the egg.
3. A barrier, which keeps other sperm out,
must be erected.
4. Nuclei and chromosomes form the egg and
sperm must unite.
Once the fertilized eggs have divided and
have therefore become "pre-embryos," they are
ready for implantation into the woman's uterus.
Transfer usually takes place 30-60 hours
post-fertilization, between the two- and eight-cell
The fertilized eggs are transferred
through the vagina and into the uterus via a thin plastic
Usually two to four eggs are transferred
during each IVF cycle. (Although the rate of pregnancy is
increased, so is the likelihood of a multiple pregnancy.)
This is an outpatient procedure and
requires no anesthesia.
After resting for a few hours, the woman
returns home and can resume normal activities within a
day or two.
This "What is
Biology Good For" was researched and written by IUPUI
student Jennifer Manske, as part of an undergraduate research
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