Simple descriptions of IVF related terms and jargon.
A
Term
Definition
Add-on
IVF 'add-ons' is another name for 'IVF optional extras' - these are anything non-essential that is used during IVF. It can include medications, procedures, laboratory techniques or alternative therapies. See IVF optional extras for all the add-ons we cover.
AMH
Anti-Müllerian Hormone: An 'AMH test' measures levels of anti-müllerian hormone, a hormone which is released by the small follicles within the ovary. An AMH result can give an indication of how an individual will respond to IVF stimulation drugs, and is often used to help IVF specialists determine which stimulation drug dosage to use.
Assisted Reproductive Technology: This term encompasses all procedures or treatments that involve handling of eggs, sperm, or embryos in a laboratory setting. It includes both IVF and ICSI, but does not include IUI.
Artificial insemination
Also referred to as intrauterine insemination (IUI). A process that involves inserting prepared semen through the neck of the womb (cervix) and into the uterus, close to the time of ovulation.
B
Term
Definition
Blastocyst
An embryo that has developed for five to six days after fertilisation. A blastocyst usually has about 100 cells.
C
Term
Definition
Cervix
The
opening to the uterus/womb.
Clinical pregnancy
A pregnancy confirmed on
ultrasound (seeing a gestational sac and heartbeat) usually around 6-8 weeks
into gestation.
Conference
abstract
A short
summary of a research project that is shared at a conference (approx 250
words). It usually provides a quick overview of the key points, such as the
purpose of the research, the methods used, the main findings, and why it’s
important. Conference abstracts usually contain too little information to
properly assess whether the study methods were appropriate and if the
study results have been reported accurately. They do not undergo peer-review
like full-length research publications. Information from a conference
abstract therefore usually needs to be taken with a grain of salt, until
further information from the study becomes available or is provided directly
by the research team.
A type of steroid
medication taken in preparation for embryo
transfer, such as prednisolone or dexamethasone. This
is an optional extra or add-on.
Cryopreservation
The
process of freezing biological material, such as eggs, sperm, or embryos, for
future use.
Cumulative success rate
IVF success rates can be reported in many different ways, which can make it difficult to understand your chances of having a baby and to compare results between IVF clinics or with different IVF options. In general, IVF success can be considered as either the chance of having a baby from
One attempt (e.g. one egg retrieval and one embryo transfer, or one frozen embryo transfer)
One complete IVF cycle (e.g. one egg retrieval and multiple embryo transfers including fresh and frozen embryos) – this is called the cumulative chance.
Thinking about IVF results in terms of the cumulative results is important for IVF treatment add-ons like PGT-A testing.
D
Term
Definition
E
Term
Definition
Ectopic pregnancy
When an embryo develops outside
of the uterus/womb, usually in the fallopian tube. This type of pregnancy is
not viable and can pose a serious risk to the health of the pregnant person
if left untreated.
Egg (or
oocyte)
A
female reproductive cell.
Egg retrieval procedure
A surgical procedure to remove
eggs from the ovaries. Also known as 'egg pick up' or 'oocyte pick up'. It is one of many steps in an IVF cycle.
Embryo
When a
sperm fertilises an egg it creates an embryo. The embryo undergoes rapid cell
division so that by the time it is a blastocyst at 5-6 days old, it has
approximately 100 cells.
Embryo
transfer media containing hyaluronic acid. This is an optional extra or add-on.
Embryo
transfer
The
process of transferring embryos from the culture in which they have been
developing in the lab, into the uterus. It is one of many steps in an IVF cycle.
Endometrial receptivity array - a brand
of endometrial receptivity testing. This is an optional extra or add-on.
F
Term
Definition
Fallopian tubes
Tubes connected to the uterus
and positioned near the ovaries. Natural fertilisation of the egg and sperm
occurs in the fallopian tubes.
Fertility
preservation
Preserving
fertility usually involves freezing eggs, sperm, embryos or reproductive
tissue for future use.
Follicle
A fluid filled sac in the ovary
in which an egg grows and develops.
Follicle
tracking
A
series of ultrasound scans to follow the development of a follicle to see if
an egg is developing. These scans are internal scans, where the ultrasound
probe is placed in the vagina.
FSH
Follicle-stimulating hormone.
This hormone is produced by the body and stimulates the growth of ovarian
follicles in the ovary before the release of an egg from one follicle at
ovulation. In the setting of ART (e.g. IVF), manufactured FSH is given to patients
in high doses to stimulate the production of multiple follicles/eggs that are
then obtained via an egg retrieval procedure.
Fresh
embryo transfer
Transferring
an embryo into the uterus between 2-6 days after it was created
(soon after egg collection), without freezing the embryo beforehand. It is one of many steps in an IVF cycle.
Frozen embryo transfer
A transfer of a embryo into the uterus/womb, using
an embryo that has been previously collected and frozen through
cryopreservation and then thawed before the embryo transfer. It is one of many steps in an IVF cycle.
G
Term
Definition
Gametes
Female
eggs and male sperm.
Genetic testing
A test that looks at your genes
to see whether you carry a particular genetic condition, and estimates how
likely you are to pass it on to your baby. This is different to genetic testing of embryos, such as PGT-A testing.
Gestation
The
period of time from the first day of a menstrual cycle to birth. It is also
used to describe how many weeks pregnant someone is. For example, at 20 weeks
pregnant, it has been 20 weeks since the first day of their last menstrual
period.
Gonadotrophins
Gonadotrophin is a broad term
that covers a group of reproductive hormones, including FSH and hCG.
H
Term
Definition
hCG
Human
Chorionic Gonadotropin (hCG) is a hormone naturally produced by the placenta
during pregnancy and is the key hormone detected by urine and blood pregnancy
tests. It is also manufactured for medical use as an injectable hormone to
assist in fertility treatments. In this context, hCG is often used as a
"trigger" injection to stimulate the final stage of egg maturation,
ensuring the eggs are ready for retrieval during a planned egg collection
procedure.
Human Fertilisation and
Embryology Authority (HFEA)
The UK wide regulator of
fertility treatment and embryo research. The HFEA produces traffic-light ratings about IVF add-ons.
Hysteroscopy
A
procedure that uses a small camera to see inside the uterus/womb.
I
Term
Definition
ICSI
Intracytoplasmic Sperm
Injection: A type of IVF where instead of mixing the sperm and egg together
for fertilisation, a single sperm is selected and injected directly into an
egg.
IMSI
Intracytoplasmic
Morphologically Selected Sperm Injection: High
magnification used to select sperm during ICSI.
This is an optional extra or add-on.
IUI
Also referred to as artificial insemination. A process that involves inserting prepared semen through the
neck of the womb (cervix) and into the uterus, close to the time of
ovulation.
IVF
In
vitro fertilisation: A procedure that involves removing eggs from a woman’s
ovaries and fertilising them in the laboratory by mixing the sperm and egg
together. This is sometimes referred to as standard IVF (compared to ICSI,
which is where the sperm is injected into the egg). There are many steps involved in a IVF cycle.
IVF add-on
IVF 'add-ons' is another name for 'IVF optional extras' - these are anything non-essential that is used during IVF. It can include medications, procedures, laboratory techniques or alternative therapies. See IVF optional extras for all the IVF add-ons we cover.
J
Term
Definition
K
Term
Definition
L
Term
Definition
Live birth
A baby is born alive, usually
after 20 weeks gestation. Births are counted as ‘birth events’, so the
delivery of twins, triplets or higher is defined as one live birth. Different
studies and data registries may define live birth slightly differently.
When
the ovaries produce fewer eggs than expected during the ovarian stimulation
phase of IVF.
M
Term
Definition
Male factor infertility
When a couple’s infertility is
caused by issues related to the person of male sex. It may result in low
sperm count or volume, poor sperm motility or low numbers of sperm with
normal morphology (shape).
Margin of error
A way of showing the statistical uncertainty associated with any statistics or numbers. A margin of error is presented as a range. The margin of error is calculated from the statistics reported in the papers and depends on the treatment effects reported in individual studies, how similar or different they are to each other, and how many people took part in the trials.
In the "More about these numbers" sections we provide the following details (as an example)
Treatment A increases the probability of having a baby from IVF.
Imagine 200 people having IVF:
100 use Treatment A
100 don’t
There will be 5 more live births among the patients using Treatment A.
This number is only approximate, and the true effect of Treatment A is probably somewhere between 1 and 9 more live births per 100 people
Here - the range of '1 to 9' represents the margin of error. It means that the actual result might not be 5, but its probably somewhere between 1 and 9.
A smaller margin of error means more confidence in the results, while a larger margin suggests more uncertainty.
Menstruation
Also
known as a ‘period’. This is the part of the menstrual cycle when a woman
bleeds from her vagina for a few days.
Miscarriage
The spontaneous loss of a
pregnancy, typically between 6 and 20 weeks gestation.
Multiple
birth
The
birth of more than one baby from a single pregnancy, such as twins or
triplets.
N
Term
Definition
Natural Killer Cells
Immune cells that help protect
the body by targeting infections and harmful cells. They are also known to be
important in the process of embryo implantation. In IVF, tests exist that
measure NK cells in the uterus or in the blood. However, the role of NK cells
in pregnancy and infertility is not fully understood, and the accuracy or
usefulness of these tests in improving IVF outcomes is unclear.
O
Term
Definition
Oestrogen
Also
known as estrogen. This is a female hormone mainly produced by the ovaries
from the onset of puberty until menopause. It promotes the growth and
maintenance of the female reproductive system.
Off-label
In Australia, medicines are approved for use by the Therapeutic Goods Administration (TGA), a government body that assesses their safety, quality, and effectiveness before they can be supplied.
Once approved, medicines may sometimes be prescribed “off label,” which means they are used in a way that differs from the specific purpose, dose, or patient group listed on the label.
Off-label use is legal and common in medical practice , especially in children and pregnant women because drugs are often not tested specifically in these groups. Off-label use is appropriate when a doctor believes it is in a patient’s best interests, explains the reasons, and discusses any uncertainties. For example, many medicines are routinely prescribed to children even though they were originally approved based on studies in adults. Other times, off label use is considered experimental and doctors should discuss the uncertainty, potential risks, and costs with patients so they can make an informed decision.
If your IVF specialist prescribes a drug off-label it means the drug is not approved for specifically for use in IVF.
OHSS
Ovarian Hyperstimulation
Syndrome (OHSS) is a potential complication of ovarian stimulation during
IVF. It occurs when the ovaries respond too strongly to hormonal medications,
leading to swollen, painful ovaries and fluid buildup in the abdomen. Symptoms
can range from mild discomfort to severe complications, including blood clots
and dehydration, requiring medical intervention.
Optional extras
Optional extras are anything non-essential that is used during IVF. It can include medications, procedures, laboratory techniques or alternative therapies. They are sometimes called ‘add-ons’.
Ovary
The
female reproductive organs that produce eggs and oestrogen on a monthly
basis.
Physiological
Intracytoplasmic Sperm Injection, sometimes called SpermSlow. Selecting sperm for
ICSI based on those which bind to hyaluronan. This
is an optional extra or add-on.
Preimplantation Genetic Testing
for Aneuploidy: A genetic test performed on embryos to check whether they have the expected number of chromosomes.
Previously known as preimplantation genetic screening or PGS. This is an
optional extra or add-on.
PGT-M
Preimplantation
Genetic Testing for Monogenic conditions: A genetic test performed on embryos
to identify specific inherited genetic conditions or diseases caused by
mutations in a single gene.
PGT-SR
Preimplantation Genetic Testing
for Structural Rearrangements: A genetic test performed on embryos to
identify specific inherited genetic conditions or diseases relating to
missing or rearranged pieces of chromosomes
For the purposes of presenting
evidence on this website, we use the definition of a ‘clinical pregnancy’
which refers to confirming a pregnancy on ultrasound (seeing a gestational
sac and heartbeat) usually at around 6-8 weeks gestation.
Also referred to as 'RCT'. A
clinical trial in which participants are randomly assigned to 2 (or more)
groups, one receiving the treatment being tested and the other receiving the
control (such as a placebo).
The loss of two or more
pregnancies in a row, typically during the first trimester. This is also
known as ‘recurrent pregnancy loss’ or RPL.
S
Term
Definition
Secondary
infertility
When a
patient who has already had a child has difficulty conceiving another.
Semen
Semen is the fluid that comes
from a penis during ejaculation that contains sperm.
Sperm
Sperm cells are male
reproductive cells that come from the testicles. They are contained in the
semen.
Sperm
motility
The
ability for sperm to move (swim) without assistance.
Sperm washing
A process where sperm cells are
separated from the rest of the semen fluid.
T
Term
Definition
Testosterone
The
male sex hormone produced in the testicles.
Tubal factor infertility
Tubal factor infertility occurs
when the fallopian tubes are blocked due to disease, damage or obstructions
that prevent the sperm from reaching and fertilising the egg.
When
the lining of the uterus (the endometrium) is thin near the time of a planned
embryo transfer.
U
Term
Definition
Unexplained infertility
Inability to identify the cause
of infertility despite a complete evaluation of semen, ovulation,
endocrinologic disorders and pelvic anatomy.
Uterus
The
womb/uterus is the female reproductive organ in which the embryo develops. At
one end, the cervix opens into the vagina, at the other, the uterus opens
into the fallopian tubes
V
Term
Definition
W
Term
Definition
Womb
The womb/uterus is the female
reproductive organ in which the embryo develops. At one end, the cervix opens
into the vagina, at the other, the uterus opens into the fallopian tubes.
X
Term
Definition
Y
Term
Definition
Z
Term
Definition
Zona
pellucida
The
shell surrounding the egg/embryo.
Zygote
A fertilised egg which is still
only one cell. Once this divides into two or more cells, it is called an embryo.
Disclaimer: Evidence-based IVF is a web-based resource that provides evidence-based information based on research and other data. Content on the Evidence-based IVF webpage is provided for information purposes only and is not intended as a substitute for medical advice. You should consult with qualified and appropriately experienced medical professionals when considering the information from this webpage. Scientific studies and clinical trial results are continually being published. While considerable care has been taken, The University of Melbourne cannot, and does not make any representations and gives no warranties that the information associated with the Evidence-based IVF webpage is in every respect correct, current, complete, reliable, or suitable for any purpose and use is entirely at your own risk.
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