Glossary of Fertility Terms - Newlife IVF Melbourne

Fertility terms

Definitions related to the creation of new life

Get to know some of the most commonly used fertility terms



  • Advanced maternal age (AMA)

    Pregnancy in a person who is 35 years or older.

  • Anovulatory

    The absence of ovulation.

  • Anti-Mullerian hormone (AMH)

    A hormone secreted by cells within early-stage follicles (fluid-filled sacs in the ovary, each containing one immature egg). The level of AMH gives an indication of the number of eggs (ovarian reserve) within the ovaries.

  • Anti-sperm antibodies

    Antibodies (immune cells) present in the blood, mucus or semen that can disrupt the movement and function of sperm. Both males and females can produce anti-sperm antibodies.

  • Antral follicles

    Small follicles in the ovaries. Antral follicles can be viewed and measured via ultrasound to predict ovarian reserve. In a natural menstrual cycle, several follicles will show growth. However, only one follicle will continue developing and release a mature egg (ovulation). Meanwhile, the remaining follicles are reabsorbed by the body. FSH injections can be used to stimulate the growth and maturation of multiple follicles, allowing them to be ‘rescued’ from reabsorption.

  • Assigned female at birth (AFAB)

    Refers to a person born with female reproductive organs.

  • Assigned male at birth (AMAB)

    Refers to a person born with male reproductive organs.

  • Assisted reproductive technology (ART)

    Any medical treatment or procedure used to help achieve pregnancy. ART includes IUI, egg freezing, IVF and much more.

  • Asthenospermia

    Suboptimal sperm motility (movement). Ideally, healthy sperm progress forward at 25 micrometres/second. Asthenospermia describes suboptimal moving sperm that are slow or sluggish, non-progressive sperm that move less than 5 micrometres/second or sperm with no motility.

  • Azoospermia

    Semen containing no sperm. Potential reasons for azoospermia include hormonal factors, lifestyle factors, prior chemotherapy or radiation, recreational substance use, prior vasectomy, and some genetic conditions.


  • Biochemical pregnancy

    A positive pregnancy blood test with no evidence of a gestational sac on ultrasound.

  • Blastocyst embryo

    The stage that a fertilised egg reaches after 5–6 days of growth. A blastocyst comprises a cavity containing two different types of cells – the inner cell mass (ICM) and the trophectoderm (outer group of cells). The ICM will become the embryo (i.e. the foetus), while the trophectoderm surrounding the ICM and cavity will become the extra-embryonic tissue (i.e. the placenta). Both groups of cells are needed for the pregnancy to continue.


  • Clinical pregnancy

    Confirmation of a pregnancy by visualising a gestational sac in the uterus or detection of heartbeat via ultrasound.

  • Corpus luteum (CL)

    After a mature follicle in the ovary releases an egg, the follicle becomes vascularised (develops a blood supply) and is known as a corpus luteum (CL). This can be seen as a blood-filled cyst in the ovary. The CL produces the hormone progesterone to prepare the uterus for embryo implantation and pregnancy. If an embryo implants into the uterus wall, it will secrete the hormone hCG, signalling to the CL that implantation has occurred. The CL will continue to produce progesterone for the first 12 weeks of pregnancy. After this, the placenta synthesises progesterone, causing the CL to cease functioning. Alternatively, if an embryo does not implant into the uterus wall, the CL will not continue producing progesterone, causing it to degenerate and trigger menstruation.

  • Cryopreservation

    This is the process of freezing reproductive eggs, sperm or embryos at very low temperatures to pause the biological activity of the cells and to preserve these cells for extended periods.

  • Cycle length

    This is measured from day one of your period (the first day of full-flow bleeding) to day one of your next period. This is generally 28 days but can range between 25–35 days.


  • Day one of cycle

    The first day of your period (full-flow bleeding).

  • Diminished ovarian reserve

    This is when the ovaries contain a lower number of eggs than expected for the person’s age. As a result, they will have lower levels of AMH – the sex hormone associated with egg production – and the eggs may be of reduced quality.

  • Donor eggs

    Eggs that are gifted or donated by the person who has generated the eggs to someone else who will use the eggs to attempt to have a pregnancy. Donor eggs can be donated by a known person or a clinic-recruited (identity release) donor.

  • Donor embryo

    An embryo that is gifted or donated by the people who generated the embryo to another person/couple that will use the embryo to attempt to have a pregnancy. Donor embryos can be from a known person or a clinic-recruited (identity release) donor.

  • Donor sperm

    Sperm that was not produced by the intended parent and was donated by someone else. Donor sperm can be donated by a known person or a clinic-recruited (identity release) donor.


  • Ectopic pregnancy

    A pregnancy where the embryo implants and grows outside the main cavity of the uterus (e.g. in the fallopian tube, ovary or cervix). An ectopic pregnancy will not result in a viable, ongoing pregnancy and can be associated with internal bleeding. Ectopic pregnancies can occur with both spontaneous and ART conceptions. One of the early indicators of an ectopic pregnancy may be low hCG levels that increase slowly or don’t progress within an expected timeframe. When hCG levels are very low and not suggestive of a viable pregnancy, your clinic may ask you to continue testing to rule out an ectopic pregnancy.

  • Egg collection/egg retrieval/egg pick up/ovum pick up (OPU)

    A procedure performed in theatre to aspirate (withdraw from the body) the fluid from mature follicles in the ovaries to retrieve eggs. An egg collection needle is attached to an ultrasound probe and inserted into the vagina. The follicles are located using ultrasound guidance. The needle is then passed through the vagina, inserted into the follicle and the follicular fluid containing the egg is aspirated into test tubes. This process is repeated until all appropriate follicles from both ovaries (if present) are aspirated. An embryologist will examine the collected fluid and isolate the eggs and their support cells.

  • Egg freezing

    The process of freezing and storing eggs for future use. After the eggs are retrieved and their support cells are removed, the eggs are placed into cryoprotectants (substances that prevent freezing damage) and frozen using a method called vitrification. This pauses the metabolic activity of the eggs. So the age of the person at the time of egg retrieval is the ‘age’ of the eggs. Upon thawing, frozen eggs behave like fresh IVF eggs. While their potential is unknown, they have a good chance of fertilising, becoming embryos and resulting in a pregnancy. The more eggs that are frozen, the higher the likelihood of pregnancy.

  • Embryo

    An egg that has been fertilised by a sperm and commences development. In IVF, the embryo is usually cultured (grown in the laboratory) until day 5–6 after insemination.

  • Embryo transfer

    Embryo transfer: The process where an embryo is transferred into the uterus using a fine tube called a transfer catheter. To maximise the chances of a successful pregnancy, the embryo transfer is timed when the uterus is most receptive. Medications may be required to support uterine receptivity, depending on the cycle type and the individual.

  • Endometriosis

    A condition where tissue like the endometrium (the inner lining of the uterus) grows outside the uterus, such as on the ovaries and fallopian tubes. This tissue also sheds like endometrial tissue with each menstrual cycle. Endometriosis can be mild to severe. Depending on location and severity, endometriosis can cause pain and affect fertility.

  • Endometrium

    The mucous membrane lining the uterus, which thickens during the menstrual cycle in preparation for possible implantation of an embryo and sheds (menstruation) if implantation doesn’t occur.

  • Estrogen/oestrogen

    A group of hormones produced by follicles in the ovaries during the reproductive cycle. A type of oestrogen, oestradiol (E2), is assessed during IVF cycles to monitor follicle growth.


  • Fallopian tubes

    Thin tubes that carry the egg from the ovary to the uterus. The egg and sperm meet in the fallopian tube, where fertilisation occurs. The first few cell divisions of the early embryo occur in the tube before the embryo enters the uterus for implantation.

  • Female fertility testing

    A series of tests to determine if, and potentially why, there are barriers to conception.

  • Fertility optimisation

    This is often where people will start on their fertility journey. Fertility optimisation services focus on identifying factors that could affect fertility and introducing changes to maximise it. This may include treating potential medical conditions, addressing lifestyle factors and timing intercourse to coincide with the time when a woman is most fertile.

  • Fertilisation

    The process where a sperm and egg combine and their individual genetic information (nucleus) is visible under the microscope. Two little circles called pronuclei (one derived from the egg and the other from the sperm) are present after fertilisation – these must be visible to classify an egg as fertilised.

  • Fibroids

    Growths present in the uterus wall. Fibroids affect approximately 1 in 3 women but are usually benign. However, they can impact fertility depending on their size and location.

  • Follicle

    A fluid-filled sac in the ovaries that contains an egg. The size of the follicle indicates whether there will be a mature egg inside.

  • Follicle-stimulating hormone (FSH)

    A hormone secreted by the anterior pituitary gland in the brain that promotes the growth of eggs and sperm. FSH medication is administered during IVF cycles to assist follicle growth.

  • Follicle tracking

    Monitoring the growth of the follicles in each ovary using ultrasound monitoring and blood tests.

  • Follicular fluid

    The liquid within the follicle. During egg retrieval, this fluid is aspirated (withdrawn), along with the egg in the fluid.

  • Frozen embryo transfer (FET)

    An embryo transfer using a frozen/thawed embryo. The FET recipient is monitored leading up to the procedure to ensure the embryo and uterine lining are synchronised. The embryo is thawed on the day of transfer by withdrawing it from cryostorage and exposing it to a solution that removes the cryoprotectant. The embryo is then transferred via the standard embryo transfer method. Over 97% of embryos survive freezing and thawing. Unfortunately, this also means that not all embryos survive the freeze-thaw process, and there is no way to predict which embryos will survive.


  • Gametes

    Eggs and sperm.

  • Gonadotropins

    Hormones that regulate reproductive function, including FSH and LH.

  • Gonadotropin-releasing hormone (GnRH)

    A hormone released from the hypothalamus (in the brain) that regulates the release of gonadotropins (hormones that regulate ovarian and testicular function, i.e. FSH and LH).


  • Human chorionic gonadotropin (hCG)

    A hormone produced by the implanting embryo’s trophoblast cells, and later synthesised by the placenta. This hormone signals to the ovaries that implantation has been successful and maintains the corpus luteum. As the embryo grows in the endometrium, it releases more hCG. It is important to see a significant increase in hCG levels as early pregnancy continues – this is why several blood tests are needed before the 7-week ultrasound scan. hCG is similar in structure to LH, the hormone that stimulates an egg to mature before ovulation. Because of this, hCG is used in an IVF cycle as a ‘trigger’ hormone to mimic the natural surge of LH occurring before ovulation, encouraging egg maturation in preparation for egg collection. hCG administered as a trigger hormone can be detectable in the bloodstream for up to 14 days. For this reason, IVF clinics encourage you not to perform your own pregnancy test too early, as elevated hCG from the trigger injection can lead to a false positive test.


  • Identity release

    The release of an embryo and gamete donor’s identity to the donor-conceived person. There are strict laws around identity release, which vary from state to state. Currently, people born as a result of donor conception can request donor-identifying information of the donor/s at 18 years of age in Victoria and NSW, and at 16 years of age in Western Australia. In Victoria, all identity release occurs through VARTA, a governing body, and not through the ART clinic. The clinic does not have the authority to release this information.

  • Implantation

    The process where an embryo adheres to and then burrows into the endometrium (the lining of the uterus), resulting in a pregnancy.

  • Infertility

    Inability to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse.

  • Intended parent

    A person or persons who enter into a surrogacy arrangement in an attempt to have a baby. An intended parent may be a single person or a couple who enter into an agreement with a woman (and her partner, if applicable) who will carry and birth a baby for the intended parents. A substitute parentage order is completed to transfer the legal guardianship of the baby from the surrogate to the intended parent/s. Intended parents sometimes use their own gametes (eggs and sperm) or donor gametes.

  • Intracytoplasmic morphologically selected sperm injection (IMSI)

    A technique combined with ICSI, where a high-powered microscope is used to select and then inject the ‘fittest’ sperm into a mature egg. By using a high-powered microscope, we can visualise the sperm in greater detail to assess their quality, morphology (how the sperm looks) and if there are any abnormalities, such as vacuoles (a fluid-filled space inside the head of the sperm that can reduce fertility).

  • Intracytoplasmic sperm injection (ICSI)

    A single sperm is injected into a mature egg. The procedure requires specialised micromanipulation equipment to handle the sperm and the eggs. The support cells surrounding the egg are removed, allowing the embryologist to visualise if the egg is mature. Only mature eggs are capable of fertilisation. ICSI bypasses the barriers that can impact successful fertilisation, such as the support cells and the shell of the egg, and deposits the sperm directly into the egg. The sperm and the egg then need to complete a cascade of reactions for fertilisation to occur. ICSI is mainly used for people with male factor infertility or where there have been suboptimal outcomes in previous cycles using conventional IVF. The likelihood of no eggs fertilising with ICSI is around 1–3% when more than two eggs are injected.

  • Intramuscular injection (IM)

    Injection of a medication into a muscle of the body (e.g. into the gluteal muscle).

  • Intrauterine insemination (IUI)

    A procedure where sperm are injected directly into the uterus through the vagina (using a tube called a catheter) to achieve conception. IUI helps bypass the cervical environment and delivers a concentrated and selected sperm population into the uterus.

  • In vitro fertilisation (IVF)

    A procedure where an egg and sperm are joined together outside of the body, in a specialised laboratory. The fertilised egg (embryo) is then transferred into the uterus for implantation.

  • IVF – conventional IVF/standard IVF insemination

    The egg (with its surrounding support cells) is placed in a dish and exposed to thousands of motile sperm. The dish is left for an extended period, allowing the sperm to penetrate various layers and fertilise the egg. There is a 5% chance that fertilisation will not occur. However, in the majority of these situations, fertilisation can be achieved by performing ICSI.



  • Male fertility testing

    A series of tests to determine if, and potentially why, there are barriers to conception.

  • Mandatory counselling

    In Victoria, legislation requires that patients who are undertaking fertility treatment consult with a counsellor before commencing treatment. During this one-on-one session, the counsellor will provide some resources and education about common emotional responses to treatment, enquire about the patient’s support systems and preparedness, and discuss implications of treatment including the freezing of material such as eggs, sperm and embryos. People participating in donor and surrogacy programs are also required to participate in counselling.

  • Menstrual cycle

    The period of time between day one of menstruation and the first day of your next period.

  • Miscarriage/pregnancy loss

    The spontaneous loss of an embryo or foetus before 20 weeks of pregnancy. Common symptoms of a miscarriage include bleeding and cramping pain. However, sometimes a pregnancy can miscarry without any symptoms and may only be detected on ultrasound. The miscarriage rate can range from 20% in women under 35 years old to 45% in women over 40 years old in spontaneous pregnancies. There are many causes for miscarriage, but the most common is when the embryo is chromosomally abnormal (these are called aneuploid embryos).


  • Oligoasthenoteratospermia

    Low numbers of sperm that are sluggish and look abnormal compared to normal parameters.

  • Oligospermia

    A low sperm count. Typically, sperm counts sit at or above 15 million sperm/mL. Mild oligospermia is at 10–15 million sperm/mL, moderate oligospermia is at 5–10 million sperm/mL, and severe oligospermia is between 0–5 million sperm/mL.

  • Oocyte

    An egg.

  • Ovarian cysts

    A large fluid-filled cavity on or inside the ovary.

  • Ovarian hyperstimulation syndrome (OHSS)

    A condition where the ovaries over-respond to fertility medications that stimulate egg maturation (i.e. FSH), resulting in ovarian swelling and increased hormone levels. This has a physiological impact on the body and can result in nausea, shortness of breath, abdominal bloating and pain. In severe cases, patients may require hospital admission to treat their symptoms and manage fluid balance. OHSS generally resolves completely, but it can be life-threatening in rare cases.

  • Ovarian reserve

    The estimated quantity of eggs in a person’s ovaries. A person is born with all their eggs, and their egg number starts to decline from birth with age until menopause is reached. Ovarian reserve varies significantly from person to person. Genes, medical conditions and some treatments and surgeries can affect ovarian reserve.

  • Ovarian tissue freezing

    A procedure where ovarian tissue is frozen and stored, to re-implant that tissue into the body when the person is ready. The re-implanted tissue contains eggs that have the potential to grow and mature. Ovarian tissue freezing is typically offered to preserve fertility before treatments that could damage fertility, such as cancer treatments.

  • Ovary

    The female reproductive organ that contains eggs and produces reproductive hormones.

  • Ovulation

    The process where a follicle within an ovary releases a mature egg. Ovulation occurs around two weeks before the next menstruation, which is on day 14 for an average 28-day cycle. As cycle length can range from 25 to 35 days, ovulation time will also vary from person to person.

  • Ovulation induction

    This fertility treatment typically involves taking medications (tablets or injections) to assist with egg maturation and ovulation, allowing couples to time ovulation with intercourse to improve the chances of fertilisation.

  • Ovulation tracking

    The process of monitoring changes throughout a person’s menstrual cycle to determine when ovulation is occurring. These can include alterations in vaginal mucus, sex hormone measurements and ultrasound scanning of the ovaries. By tracking ovulation, intercourse can be timed to increase the chances of conception.


  • Patient review panel (PRP)

    An independent statutory body comprising a panel of 12 people that assesses applications of patients who wish to access ART where permission is necessary under the Assisted Reproductive Treatment Act 2008 (e.g. surrogacy arrangements).

  • Percutaneous epidydimal sperm aspiration (PESA)

    Retrieval of testicular sperm from the epididymis (reproductive tube within the scrotum) for use in fertility treatments. The specialist locates the epididymis by palpating the scrotum, secures the tube and then uses a needle with suction pressure to aspirate the content of the epididymis, which usually contains sperm.

  • Polycystic ovarian syndrome (PCOS)

    An endocrine condition that can impact ovarian function, including ovulation. As a result, PCOS can cause infrequent ovulation and irregular menstrual cycles, and affect fertility.

  • Polycystic ovaries (PCO)

    An ultrasound finding of multiple follicles on the ovaries (also known as multi-follicular ovaries). Around 20% of women have PCO on ultrasound, but this does not mean they have PCOS (see above).

  • Polyps

    Growths that can be found in various places around the body, including inside the uterine cavity. Polyps are usually benign, however, uterine polyps may make it more difficult for an embryo to implant and may need to be removed.

  • Posthumous use

    In the context of ART, this refers to a person’s wishes for their gametes or embryos created with their gametes to be used following their death.

  • Pre-implantation genetic testing (PGT)

    Genetic testing of a biopsied sample of cells from an embryo, usually at the blastocyst stage. Test types include ensuring the embryo has the correct number of chromosomes (PGT-A), and screening for structural abnormalities (PGT-SR) or common genetic conditions (PGT-M). Some of these abnormalities may not be compatible with life, and implantation would result in miscarriage. PGT allows the selection of the embryo with the best chance of pregnancy.

  • Preimplantation genetic testing for aneuploidies (PGT-A)

    This is a genetic test designed to check the number of chromosomes in the embryo. An incorrect number of chromosomes is called chromosome aneuploidy, which can increase the chance of miscarriage or the birth of a baby with a chromosome abnormality.

  • Preimplantation genetic testing for monogenic or single gene defects (PGT-M)

    This involves testing an embryo in a specialised laboratory for any genetic conditions that run in families and may be passed down to the embryo – for example, cystic fibrosis.

  • Preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR)

    This involves testing the genetic blueprint of an embryo in a specialised laboratory for any abnormalities in the order of genetic information that could result in too little or too much genetic information in the embryo. Often, these changes are not viable with life, and implantation with the embryo would result in miscarriage.

  • Premature ovarian failure (POF)

    Ovarian function that halts before 40 years of age – also termed ‘early menopause’. POF is defined as having at least 12 months without a period, along with alterations in sex hormone levels that also indicate menopause.

  • Progesterone (P4)

    A hormone released by the ovaries after ovulation that supports early pregnancy.


  • Semen analysis

    A test to examine a semen sample for sperm quality, quantity and motility.

  • Sperm

    The male reproductive cell that originates in the testis. Spermatogenesis: Sperm production in the testis.

  • Spermatogenesis

    Sperm production in the testis.

  • Sperm concentration

    The quantity of sperm in the ejaculate fluid. Low sperm concentration or the complete absence of sperm can predict difficulty in achieving a spontaneous pregnancy.

  • Sperm DNA fragmentation

    Damage or fragmentation of sperm DNA. This reduces the possibility that the sperm will successfully fertilise the egg and may contribute to early miscarriage.

  • Sperm freezing

    The process of freezing and storing sperm for future use. Sperm are cryopreserved using cryoprotectant and stored at low temperatures, pausing their biological activity. The age of the person at the time of sperm collection is the ‘age’ of the sperm.

  • Sperm morphology

    The shape of the sperm – including the head, midpiece and tail. Sperm that have abnormal morphology (i.e. an abnormal appearance) may have reduced potential to successfully fertilise eggs or result in viable pregnancies.

  • Sperm motility

    The ability of sperm to swim. High numbers of poorly moving sperm are predictive of difficulty in achieving a spontaneous pregnancy.

  • Subcutaneous injection

    An injection given beneath the skin, into the fatty layer.

  • Surrogacy (gestational carrier) services

    A surrogate or gestational carrier is a person who enters into a surrogacy agreement with the intended parent/s. They agree to carry and birth a baby, and then complete a parentage order to transfer the legal guardianship of the baby from the surrogate (and her partner, if applicable) to the intended parent/s. Intended parents sometimes use their own gametes (eggs and sperm) or donor gametes. A gestational surrogate is not permitted to use her own eggs to create the pregnancy.


  • Testicular sperm retrieval/testicular sperm extraction/testicular biopsy

    A procedure requiring removal off the tubules in a testicle (where sperm are usually produced) to retrieve sperm for use in IVF or fertility preservation. There are four types of testicular sperm retrieval:

    1. Testicular sperm aspiration (TESA) – a fine needle is inserted into the testicle for sperm retrieval
    2. Percutaneous epididymal sperm aspiration (PESA) – a fine needle is inserted into the epididymis (a series of small tubes at the back of the testicle) for sperm retrieval
    3. Open biopsy (TESE) – a surgical incision is made in the testicle for sperm retrieval
    4. MicroTESE – the testis is removed from the scrotum and, using a microscope, a urologist identifies and removes tubules that look ‘healthy.’ An embryologist dissects the tubules to identify if sperm present.

  • Teratospermia

    Abnormalities in sperm shape (morphology). These include abnormalities in the head, midpiece or tail of the sperm, which can affect the ability of sperm to fertilise an egg.

  • Termination of pregnancy (TOP)

    The medical process of ending a pregnancy.

  • Testes

    The male reproductive organ that produces sperm and reproductive hormones.

  • Timed intercourse (TI)

    Monitoring when ovulation occurs and having intercourse at an optimal time to coincide with egg release.

  • Trying to conceive (TTC)

    Actively attempting to become pregnant. This could be via unprotected sex, insemination (e.g. IUI), IVF or an embryo transfer into a surrogate.


  • Ultrasound (abdominal or vaginal)

    An imaging method that visualises internal organs on a screen using sound waves administered through a probe. The probe is positioned on the abdomen, along with gel, and is moved across the abdomen until the appropriate image is gained. Patients may experience slight discomfort, particularly in instances where a full bladder is required to help visualise the pelvic organs. Abdominal ultrasound is used during an embryo transfer to see the uterus and the placement of the transfer catheter containing the embryo. A vaginal ultrasound involves placing the probe into the vagina to visualise the follicles on an ovary.

  • Uterus

    The reproductive organ in a person’s body where the foetus develops.


  • Vitrification

    An ultra-rapid freezing method used to cryopreserve eggs and embryos.