Download Glossary Of Terms

Glossary Of Terms
Abortion Spontaneous : A pregnancy loss during the first twenty weeks of
gestation. Habitual: When a woman has had three or more miscarriages.
Incomplete: An abortion after which some tissue remains inside the uterus. A D&C
must be performed to remove the tissue and prevent complications. Missed: The
foetus dies in the uterus but there is no bleeding or cramping. A D&C will be needed
·to remove the foetal remains and prevent complications. Therapeutic: A procedure
used to terminate a pregnancy before the foetus can survive on its own. Threatened:
Spotting or bleeding that occurs early in the pregnancy. May progress to
spontaneous abortion.
Amniocentesis A prenatal test used to diagnose certain foetal abnormalities. The
pregnant woman is given a local anesthetic and needle is inserted through her
abdominal wall and into the cavity of her uterus. A sample of amniotic fluid, which
surrounds the foetus, is withdrawn. The extracted fluid contains foetal cells which
are artificially cultured and analyzed with chemical and microscope tests for
chromosome abnormalities (e.g. Down's syndrome), biochemical (metabolic)
abnormalities, neural tube defects(NTDs). The chromosome analysis shows the sex
of the foetus. Amniocentesis is performed after the 14th week of a woman's
pregnancy, usually not after the 16th week. Only some birth conditions are
detectable by this method. It carries a risk of miscarriage and can damage the foetus.
(See sex selection.)
Artificial insemination (AI) A simple procedure by which spermatozoa are
deposited in a woman's vagina close to the cervix. Alli designates artificial
insemination by husband or homologous artificial insemination, when the
spermatozoa come from the husband. AID designates artificial insemination by
donor, when the spermatozoa comes from a (usually anonymous) donor. Many
women simply use the term "insemination" to describe the practice.
Artificial womb See ectogenesis
Assisted reproductive technology (ART) Several procedures employed to bring
about conception without sexual intercourse, including IUI, IVF, GIFT and ZIFT.
Azoospermia Semen containing no sperm, either because the testicles cannot make
sperm
or
because
of blockage
m the
reproductive
tract.
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Chorionic villi sampling (CVS) or Chorion biopsy (CVB) A prenatal screening
procedure for analysis of foetal tissue. A small amount of chorion tissue surrounding
the foetus is removed through the pregnant woman's cervix. It is a relatively new
experimental procedure. It is performed earlier than amniocentesis, at eight to 14
weeks of pregnancy. Like amniocentesis it can be used for sex selection, and carries
ri5k of miscarriage. Results can be evaluated overnight.
Chromosome The structures in the cell that carry the genetic material (genes); the
genetic messengers of inheritance. The human has forty-six chromosomes,
twenty-three coming from the egg and twenty-three coming from the sperm.
Clone Genetically identical organisms. They are produced from a single individual
by asexual reproduction, that is, Without union of egg and sperm. (in sexual
reproduction the genetic make-up of each offspring is unique, with contributions of
genetic material coming from egg and sperm.) In mammals clones can be produced
by inserting a foreign nucleus into an unfertilized egg or by embryo division. Cells
and genes can. also be cloned. Cloning, like most reproductive technologies, has
great commercia! and eugenic possibilities. Embryo division is a cloning method
already being used in mammals (such as cows), and thus could be used on human
IVF embryos.
Another type of cloning occurs by "nucleus substitution" (also called "nuclear
transplantation"). The nucleus is removed from an unfertilized egg cell and replaced
with a new nucleus taken from a donor cell. The egg can then develop as of it were
fertilized. Researchers suggest that this type of cloning could be used with human
eggs to grow human tissues and organs needed for a person who required a
transplant. Women's bodies would be needed to supply the human eggs.
Clomid The trade name for clomiphene citrate, a fertility drug. It is a weak
synthetic estrogen which may induce ovulation by interfering with the estrogen
receptors in the woman's brain. Presumably the brain is stimulated to induce the
production of hormones necessary for ovulation. The drug has many adverse effects,
including ovarian enlargement, and in some cases it can contribute to fertility
problems by adversely effecting the post-ovulatory phase of a-women's menstrual
cycle. It is also used in IVF, usually to promote superovulation (see superovulation).
Conception The fertilisation of a woman's egg by a man's sperm resulting in a an
embryo.
,
Congenital defect or birth defect Congenital means present at birth. Congenital
defects are not necessarily genetic defects. Congenital defect may be due to (a)
genetic factors (chromosomal defects of "faulty" gene defects); (b) injury or
infectious disease during pregnancy (e.g. Rubella); (c) environmental factors such as
drugs (e.g. thalidomide), chemicals (e.g. dioxin), and radiations; (d) combinations of
hereditary and environmental factors. (We consider the term "defect" to be
subjective and pejorative).
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Depo-Provera A long-lasting injectable contraceptive, designed to be administered
to women once every three months. It is a synthetic progesterone which can block
egg production, interfere with the development of her uterine lining during her
menstrual cycle, or interfere with egg transport in her fallopian tube. Manufactured
by the Upjohn Corporatiori, it has never been approved as a contraceptive in the US.
It is available in the UK, and it has been widely promoted by international aid
agencies in the Third World. Little is known of its long-term effects, but they may
include alterations of a woman's immunological system and birth defects if the drug
remains in a woman's system while she is pregnant. There are many immediate
possible effects, including the cessation of menstrual bleeding (at lower dosage
relative to contraceptive use), in conjunction with IVF pregnancies in one IVF
program in Australia.
Dilation and curettage (D&C) A procedure used to dilate the cervical canal and
scrape out the lining and contents of the uterus. The procedure .can be used to
diagnose or treat the cause of abnormal bleeding and. to terminate an unwanted
pregnancy.
Ectogenesis The complete development of a human foetus outside a woman's
womb, in an "artificial womb." Advances in neonatal technology and keeping
embryos alive in vitro contribute to the possibility of developing an "artificial
womb".
Egg donation A process whereby a fertile woman donates an egg to be fertilized in
vitro by the semen of the partner of an infertile woman.
Embryo Commonly, the early stage in development, each cell of a fertilized
mammalian egg has the potential to grow into a complete organism. Embryo
division is a laboratory technique, the splitting of an in vitro embryo at a stage when
each section may continue development. This is one form of cloning and it has been
used successfully on cows in the agriculture industry and in laboratories for
research. In human embryos, the developing fertilized egg (usually in its four-cell
stage called the blastula) could be divided into individual cells which could then
develop into four identical human beings. Researchers have suggested one or more
of the cells could be investigated to determine their genetic composition.
Embryo donation A process whereby a donated egg s fertilized by donated sperm
in vitro and the resulting embryo transferred to a woman who is herself infertile and
whose partner is infertile.
Embryo replacement A method used in conjunction with IVF treatment, in which
the developing IVF embryo in inserted in the womb of the same woman whose egg
is used. British IVF pioneers Robert Edwards and Patrick Steptoe use this term in
preference to embryo transfer.
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Embryo transfer (ET) The method of inserting an embryo into a woman's womb.
The embryo can be an IVF embryo or an embryo flushed from a woman's womb
before implantation. The woman who receives it might be the same woman whose
egg is used for IVF, or she might be a second woman, who did not contribute her
own egg to the embryo.
Estrogen A collective term for a group of naturally occurring hormones with a
variety of functions. The estrogen estradiol is necessary for the complete maturation
of eggs during a woman's menstrual cycle. Synthetic estrogens are drugs produced
in laboratories; they are similar in chemical structure to naturally occurring
estrogens, but they are not identical. Their function is to alter or interfere with the
production of menstrual cycle hormones.
Eugenics Suggestions for improvement of human genetic material. The science of
the improvement of the human species by genetic means championed by Sir Francis
Galton ( 1822-1911) who proposed the idea of improving physical and mental
characteristics by selective parenthood. It was the basis of the compulsory
sterilization laws passed in many countries in the early twentieth century and the
Nazi's "racial hygiene" program.
Foetus Commonly, the developing embryo which has achieved recognizable human
features, about eight weeks onward in humans. Scientific usage varies.
Genetic engineering The use of experimental techniques to change the
characteristics of an organism by altering its DNA Genetic engineering is an
all-embracing term for anything from cloning to recombinant DNA technologies
(gene manipulation techniques).
Genetic screening The use of a variety of diagnostic tests to acquire genetic or
partly genetic information about an individual. In reproduction it is used to identify
carriers of heritable genetic conditions which may be transmitted to offspring, and to
identifY certain congenital abnormalities in a foetus. ·Genetic engineering technology
is expanding the scope of genetic screening; diagnostic tests are being developed to
identifY genetically related "susceptibility" to certain diseases or genetically related
"sensitivity" to toxins in the environment; DNA fingerprinting is all application of
genetic screening being used in police work.
Genetics The science aimed at understanding what genes are and how they work.
Genetics comprises the study of a wide range of biological processes influenced by
genes, including embryo development, metabolism, genetic disease, etc. Modem
genetics began before the "gene" was actually discovered: it began as the branch of
biology which deals with heredity and variation and the origin of individual
characteristics.
Genome The genetic complement of an organism taken as a whole.
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Human menopausal gonadotropin (HMG) A commercial preparation of two
honnones (FSH and LH, follicle-stimulating hormone and luteinizing honnone)
necessary for ovulation. It is extracted from the urine of newly menopausal women.
HMG stimulates follicle development. It is extremely powerful and the risks include
over-stimulation of the woman's ovaries and enlargement ofher ovaries.
In vitro Literally, "in glass". It is used in science to describe biological processes,
which are made to occur outside the living body, in laboratory apparatus. Compare
in vivo.
In vitro fertilization (IVF) Joining of egg and sperm outside the female body. Egg
and spenn are placed in a laboratory dish in a culture medium which contains
nutrients and substances necessary for growth. It necessitates using other laboratory
and medical procedures on women, that is, in vitro fertilization includes a number of
other procedures, such as superovulation and embryo transfer. The risks to women
and offspring are unknown.
In vivo Literally, "in life". It is used in science to describe biological processes
which are observed occurring in their natural environment within the living
organism.
Laparoscopy Visual examination of a women's ovaries (or other abdominal organs)
by insertion of a light guide through a small incision in her abdominal wall. Her eggs
can be removed during laparoscopy, by the insertion of a suction device and forceps
for grasping the woman's ovary. It is a surgical procedure requiring anesthesia and
the distension of her abdomen with a carbon dioxide gas mixture.
Norplant
An experimental long-lasting subdermal hormonal (synthetic
progesterone) contraceptive. The drug is implanted under the woman's skin and is
effective for five years.
Neural tube defect (NTD) The neural tube is formed early in the development of
the nervous system, at about five weeks in the human foetus. NTDs are thought to
occur when the neural tube fails to form properly. NTDs include anencephaly
(severe deformity of the brain) and the various forms of spina bifida (malformation
of the spinal column).
Pergonal The trade name for the fertility drug human menopausal gonadotropin
(HMG).
Progesterone A honnone produced in a woman's ovaries after ovulation and also
by the placenta. Among other functions, it influences the further development of the
uterine lining during her menstrual cycle. Synthetic progesterone (sometimes called
progestin) were developed for use as contraceptives. They work by interfering with
the processes necessary for ovulation, egg movement, development of the uterine
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ining and cervical mucus production. They have immediate adverse effects, such as
irregular bleeding. Little is known of long-term effects, and risks may include loss of
fertility and alterations in the woman's immunological system. Depo-Provera and
other long-lasting injectable are synthetic progesterone. As drugs they are also used
to treat premenstrual tension.
Reproductive technology (RT) The full range of biomedical/technical interventions
during the process of procreation, whether aimed at producing a child or preventing/
terminating a woman's pregnancy. It therefore includes the newer technologies
(NRTs) such as IVF, sex preselection, or cloning, but also contraceptives,
sterilization techniques, abortion, genetic screening, and other related genetic
technologies. The "new reproductive technologies" usually refer to artificial
reproduction techniques (including genetic techniques) accomplished by in vitro
methods.
Sex-selection A term which refers to either (a) the identification of the sex of an
already existing embryo or (b) the choice of the sex of an embryo before fertilization
occurs, more accurately called sex preselection. Both types of sex selection are
promoted for negative eugenic reasons, that is as a means to avoid sex-linked
genetic disorders such as hemophilia, which only occurs in male offspring. Sex
selection is also being promoted by many advocates for sex preference selection.
Sex preselection techniques are already being offered in the US to people who
simply prefer to predetermine the sex of the offspring. Amniocentesis and chorionic
villi sampling are used to select for male babies in India and in China.
Sexually transmitted disease (STD) Infections pertaining to, or transmitted during
sexual intercourse. Also known as VD or venereai diseases. Most commonly
gonorrhea, syphilis,and chlamydia and now AIDS.
Sterilization A surgical procedure whose purpose is to render a person unable to
reproduce. The most common type of sterilization for women today is tubal
ligation. Other types are hysterectomy (removal of the uterus) and oophorectomy
(removal oftheovaries).
Superovulation The woman undergoing IVF treatment is given a regimen of
fertility drugs and hormones to stimulate her ovaries to produce many eggs. It
carries risk of damaging her ovaries. Also called hyperovulation.
Surrogacy, full The term used by Peter Singer and Deane Wells to describe a
process in which the carrying mother does not contribute any genetic material. The
egg of the female half of the commissioning couple is fertilized in vitro by the sperm
of her male partner, and then transferred to the carrying mother.
Surrogacy, partial Where the carrying mother is also the genetic mother of the
child. The carrying mother is either artificially inseminated or has intercourse with
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the would-be father.
Surrogate mother A woman who becomes pregnant and canies a child for another
person or couple.
Trans vaginal ultrasound-directed oocyte recovery (TUDOR) A method of
collecting a woman1s eggs for IVF, introduced as an alternative to laparoscopic egg
retrieval. A needle for pulling out mature eggs is inserted through her vagina and
into her bladder and toward her ovary. The ultrasound picture is used by the doctor
moving the needle. In this procedure a woman1s eggs are more difficult to grasp than
in laparoscopic egg retrieval, and it is painful. It canies high risk of infection because
of piercing of the woman1s bladder.
Ultrasound scanning In medicine, high frequency sound waves are used to show
visual outlines of internal bodily structures. The picture is shown on a television
screen or traced on a sheet of paper. It is used to visualize the foetus inside the
woman1S womb to (a) determine foetal growth and gestational age and (b) to look
for 11 abnormalities 11 of the uterus, placenta, and foetus. Ultrasound by itself can and
is misused to ascertain foetal sex. In IVF treatment vaginal ultrasound is used to
monitor the woman1s ovulation and as part of egg recovery (see TUDOR).
Ultrasound is now widely used and often assumed to be safe, though no long-term
studies on its effects have as yet been reported. Also called ultrasonography,
sonogram, and ultrasound visualization.
Donor insemination
Insemination.
Artificial insemination with donor sperm. See Artificial
Ectopic pregnancy A pregnancy outside of the uterus, usually in the fallopian tube.
Egg retrieval A procedure used to obtain eggs from ovarian follicles for use in vitro
fertilization. The procedure may be performed· during laparoscopy or by using a long
needle and ultrasound to locate the follicle in the ovary.·
Ejaculate The semen and sperm expelled during ejaculation.
Endometriosis A condition where endometrial tissue is located outside the womb.
The tissue may attach itself to the reproductive organs or to other organs in the
abdominal cavity. Each month the endometrial tissue inbreeds with the onset of
menses. The resultant irritation causes adhesions in the .abdominal cavity and in the
fallopian tubes. Endometriosis may also interfere with ovulation and :with the
implantation of the embryo.
Fallopian Tubes Ducts through which eggs travel to the uterus once released from
the follicle. Sperm normally meet the egg in the fallopian tube, the site at which
fertilization usually occurs.
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Fertility Treatment Any method or procedure used to enhance fertility or increase
the likelihood of pregnancy, such as ovulation induction treatment, varicocele repair,
and microsurgery to repair damaged fallopian tubes. The goal of fertility treatment is
to help couples have a child.
Follicle stimulating hormone (FSH) A p1twtary hormone that stimulates
spermatogenesis and follicular development. In the man FSH stimulates the sertoli
cells in the testicles and supports sperm production. In the woman FSH stimulates
the growth of the ovarian follicle. Elevated FSH levels are indicative of gonadal
failure in both men and woman.
Follicles Fluid-filled sacs in the ovary which contain the eggs released at ovulation.
Each month an egg develops inside the ovary in a fluid filled pocket called a follicle.
This follicle is one inch in size and is about ready to ovulate.
Gonadotropins
Hormones which control reproductive function: Follicle
stimulating hormone (FSH) and Leutenizing hormone (LH).
Gonadotropin releasing hormone (GNRH) The hormone which controls the
production and release of gonadotropins. Secreted by the hypothalamus every ninety
minutes or so, this hormone enables the pituitary to secrete LH and FSH, which
stimulate the gonads. See FSH and LH.
Hyperstimulation, Ovarian hyperstimulation syndrome (OHSS) A potentially
life-threatening side effect of Pergonal, Humagon or Metrodin ovulation induction.
A woman's ovaries become enlarged and produce an overabundance off eggs.
Blood hormone levels rise, fluid may collect in the lungs or abdominal cavity, and
ovarian cyst may rupture, causing internal bleeding. Blood clots sometimes develop.
Symptoms include sudden weight gain and abdominal pain. Cycles stimulated with
these drugs must be carefully monitored with ultrasound scans. OHSS may be
prevented by withholding the HCG injection when ultrasound monitoring indicates
that too many follicles have matured.
Impotence The inability of the man to have an erection and to ejaculate.
Intra uterine insemination (lUI) A relatively "low-tech" ART, which deposits
"washed" sperm directly into the uterus, bypassing cervical mucus and depositing
the sperm more closely to the fallopian tubes, where fertilization occurs. Used to
bypass hostile cervical mucus and to overcome sperm count and mobility problems.
See Artificial insemination.
Luteinizing hormone (LH) A pituitary hormone that stimulates the gonads. In the
man LH is necessary for spermatogenesis (sertoli cell function) and for the
production of testosterone (Ieydig cell function). In the woman LH is necessary for
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the production of estrogen. When estrogen reaches a critical peak, the pituitary
releases a surge ofLH (the LH spike), which releases the egg from the follicle.
Luteinizing hormone surge (LH Surge) --- The release of luteinizing hormone (LH)
that causes release of a mature egg from the follicle. Ovulation test kits detect the
sudden increase of LH, signaling that ovulation is about to occur (usually within
24-36 hours).
Miscarriage
Abortion.
Spontaneous loss of an embryo or foetus from the womb. See
Oligospermia Having few sperm.
Ovaries The female sex gland which produces the hormones estrogen and
progesterone and in which the ova are developed.
Ovarian failure The failure of the ovary to respond to FSH stimulation from the
pituitary because of damage to or malformation of the ovary. Diagnosed by elevated
FSH in the blood.
Ovarian cyst A fluid-filled sac inside the ovary. An ovarian cyst may be found in
conjunction with ovulation disorders, tumors of the ovary, and endometriosis.
Ovulation The release of the egg (ovum) from the ovarian follicle.
Ovum The egg; the reproductive cell from the ovary; the female gamete; the sex ceQ
that contains the woman's genetic information.
.Pelvic inflammatory disease (PID) An infection of the pelvic organs that causes
severe illness, high fever, and extreme pain. PID may lead to tubal blockage and
pelvic adhesions.
Polycystic ovaries (PCO or "Stein-Leventhal Syndrome") A condition found in
women who do not ovulate, characterized by excessive production of androgens
(male sex hormones) and the presence of cysts in the ovaries. Though PCO can be
without symptoms, some include excessive weight gain, acne and excessive hair
growth.
Prolactin The hormone that stimulates the production of milk in breast-feeding
women. Excessive prolactin levels when not breast-feeding may result in infertility.
Secondary Infertility The inability of a couple to achieve a second pregnancy. This
strict medical definition includes couples for whom the pregnancy did not go to
term. The common vernacular, however, refers to a couple which has one biological
child but is unable to conceive another.
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Semen The fluid portion of the ejaculate consisting of secretions from the seminal
vesicles, prostate gland, and several other glands in the male reproductive tract. The
semen provides nourishment and protection for the sperm and a medium in which
the sperm can travel to the woman's vagina. Semen may also refer to the entire
ejaculate, including the sperm.
Sperm The microscopic cell that canies the male's genetic information to the
female's egg; the male reproductive cell; the male gamete.
·
Sperm bank A place where sperm are kept frozen in liquid nitrogen for later use in
artificial insemination.
Sperm count The number of sperm in ejaculate. Also called sperm concentration
and given as the number of sperm per millilitre. ·
Sperm motility The ability of sperm to swim. Poor motility means the sperm have a
difficult time swimming toward their goal i.e. the egg.
Sterility An irreversible condition that prevents conception.
Surrogate mother A woman who is artificially inseminated and canies to term a
baby which will be raised by its genetic father and his partner.
Uterus The hollow, muscular organ that houses and nourishes the foetus during
pregnancy.
Vas deferens One of the tubes through which the sperm move from the testicles
(epididymis) toward the seminal vesicles and prostate gland. These tubes are severed
during a vasectomy performed for birth control.
Vasectomy The accidental or elective surgical separation of the vasa deferential, a
procedure used for birth control.
X Chromosome The congenital, developmental, or genetic information in the cell
that transmits the information necessary to make a female. All eggs contain one X
chromosome, and half of all sperm carry an X chromosome. When two X
chromosome combine, the baby will be a girl.
Y Chromosome The genetic material that transmits the information necessary to
make a male. The Y chromosome can be found in one-half of the man's sperm cells.
When an X and a Y Chromosome combine, the baby will be a boy.
Zygote A fertilized egg which has not yet divided.
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References:
Patricia Spallone and Deborah Lynn Stienburg (eds.) (1987) Made to Order: The
Myth ofReproductive and Genetic Progress, Pergamon, Oxford.
InterNational Council on Infertility Information Dissemination (1996) INCIID
Glossary: Fertility Terms and Acronyms, http//www.inciid.orglglossary/html
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