Understanding IVF terminology: Common terms, procedures, and acronyms explained

On this page:

What is IVF?

Common IVF terms explained

Anti-Müllerian hormone (AMH) test

Follicle-stimulating hormone (FSH) test

Ovarian reserve

Ovarian stimulation

Egg retrieval

Egg fertilisation

Sperm motility

Sperm morphology

Sperm count

Blastocyst

Embryo grading

Embryo transfer

Fresh vs frozen embryo transfer

Natural vs medicated cycle

Implantation

Luteal phase support

Two-week wait

Beta-hCG test

Common IVF procedures

Understanding IVF acronyms

Why understanding IVF terminology matters

FAQs about IVF terminology and procedures

What is IVF?

Dr  Guimarães explains:

“IVF stands for in vitro fertilisation. It is a fertility treatment used to help people achieve pregnancy. During IVF, eggs are collected from the ovaries and fertilised with sperm in a laboratory.”

Once fertilised, the resulting embryo (or embryos) can be:

• Transferred into the uterus, where it can implant and grow into a pregnancy, or
• Frozen for future use if needed.

Visit our page on IVF treatment to learn more about the step-by-step process of IVF.

Common IVF terms explained

According to Dr  Guimarães, here are some key terms you will come across during your fertility journey:

Anti-Müllerian hormone (AMH) test

The AMH test is a fertility test that measures the level of anti-Müllerian hormone in your blood. This hormone is produced by small follicles in the ovaries and gives doctors an idea of your ovarian reserve, meaning how many eggs you might have left.

Higher AMH levels generally suggest a higher number of eggs, while lower levels can indicate a lower ovarian reserve. The level of this hormone is stable along the menstrual cycle.

According to Dr  Guimarães:

“It is important to know that AMH does not measure egg quality, only quantity. Your doctor uses AMH results alongside other tests to plan the best treatment approach for you.”

Follicle-stimulating hormone (FSH) test

The FSH test is another type of fertility test, which measures the level of follicle-stimulating hormone in your blood, usually taken early in your menstrual cycle. FSH plays a key role in helping your ovaries develop follicles (the small sacs that contain eggs).

If your FSH levels are higher than expected, it might be a sign that your ovaries are working harder to stimulate egg development, which can be a sign of reduced ovarian reserve.

Like AMH, FSH is just one piece of the puzzle and is combined with other results to create a full picture of your fertility health.

To learn about other types of fertility tests, read our guide: Fertility tests for women: 10 types of checks to test your fertility.

Ovarian reserve

Ovarian reserve refers to the number and quality of eggs remaining in your ovaries. It is an important factor in fertility and can influence how you respond to IVF treatment.

Everyone is born with all the eggs they will ever have. As you age, your ovarian reserve naturally declines, and the quality of your eggs can decrease too. This is why female fertility generally starts to decline after the age of 35.

Your fertility specialist may recommend tests such as the AMH (Anti-Müllerian Hormone) blood test or an antral follicle count (AFC) scan to estimate your ovarian reserve. These results help your doctor personalise your stimulation plan and better predict how many eggs might be retrieved during your IVF cycle.

Dr  Guimarães says:

“A lower ovarian reserve does not mean you cannot get pregnant, but it might affect the number of eggs available and the approach your team recommends.”

For more information on ovarian reserve and fertility, read our guide, Female fertility: when are you most fertile and what causes infertility.

Ovarian stimulation

Ovarian stimulation is the first major step in an IVF cycle. During a non-IVF or natural cycle, your body selects just one egg from a group of available eggs, called a cohort, to mature and be released during ovulation.

The remaining eggs in that cohort naturally stop developing and are reabsorbed by the body.

With ovarian stimulation, hormone medications are used to encourage all the eggs in that month’s cohort to grow at the same time.

Instead of losing the extra eggs, doctors can collect several mature eggs at once during egg retrieval. Having more eggs available increases the chances of creating healthy embryos that can be transferred immediately or frozen for future use.

The number of eggs in each cohort can vary depending on several factors, including:

• Age: Younger women usually have larger cohorts of eggs, while women over 35 may have smaller cohorts.
• Ovarian reserve: Women with a higher ovarian reserve tend to produce more eggs in response to stimulation. Those with a lower ovarian reserve may produce fewer eggs.

Your fertility specialist will personalise your ovarian stimulation plan based on these factors to optimise your response and give you the best possible outcome.

Egg retrieval

Egg retrieval, also called “egg collection,” is a key step in the IVF process. It is a minor surgical procedure that removes eggs from your ovaries for fertilisation in the laboratory.

Here is what happens during egg retrieval:

• You receive light sedation to keep you comfortable.
• The doctor uses ultrasound guidance to locate your ovarian follicles.
• Each follicle is a small fluid-filled sac that usually contains a developing egg.
• A thin needle is used to gently aspirate (suction) the fluid from each follicle.

It is important to know that not every follicle contains an egg. Some follicles may be empty, and others might contain eggs that are not yet mature. This is completely normal.

After the procedure:

• The collected fluid is taken immediately to the laboratory.
• The embryologist examines the fluid to find and collect the eggs.
• The mature eggs are then prepared for fertilisation.

Dr  Guimarães says:

“The number of eggs retrieved depends on how many follicles developed and how many contained mature eggs. Your fertility team will explain the results to you after the procedure.”

Egg fertilisation

After the eggs are retrieved, they are taken to the laboratory for fertilisation. Depending on the situation, fertilisation can happen in different ways.

• In standard fertilisation, eggs and sperm are placed together in a special dish to allow natural fertilisation.
• In ICSI (intracytoplasmic sperm injection), a single sperm is injected directly into an egg, often used when there are sperm quality issues.

Sperm is usually collected on the same day as egg retrieval. Most patients provide a semen sample, but if needed, sperm can be retrieved surgically:

• TESA (Testicular Sperm Aspiration) uses a needle to collect sperm directly from the testicle.
• TESE (Testicular Sperm Extraction) removes a small sample of testicular tissue to find sperm.
• In some cases, donor sperm may be used. This option is often chosen when there are severe male fertility issues, a risk of passing on a genetic condition, or for single women and same-sex couples. Donor sperm is carefully screened and prepared in the laboratory to ensure the best possible chances of fertilisation.

Once fertilisation occurs, the embryos are monitored closely in the lab as they begin to develop.

Sperm motility

Sperm motility refers to how well sperm moves. During a semen analysis, sperm are examined under a microscope to assess how actively and efficiently they are swimming. Healthy sperm need to move strongly and in a straight line to reach and fertilise an egg.

Dr  Guimarães says:

“Poor sperm motility can make it harder for natural fertilisation to happen. In these cases, techniques like ICSI (intracytoplasmic sperm injection) may be recommended during IVF.”

Sperm morphology

Sperm morphology refers to the size and shape of the sperm. During a semen analysis, the sperm are examined under a microscope to see if they have a normal structure, including a smooth oval head, a midpiece, and a tail that moves properly.

Abnormal shapes can make it harder for sperm to swim to the egg or fertilise it.

According to Dr  Guimarães:

“Some variation is normal, but a higher percentage of well-shaped sperm can increase the chances of successful fertilisation.”

Sperm count

Sperm count measures the number of sperm present in a semen sample. It includes both the concentration (how many sperm are in each millilitre of semen) and the total number of sperm in the whole sample.

A higher sperm count can increase the chances of fertilisation, while a lower sperm count might make conception more difficult. However, many people with low sperm counts still achieve pregnancies, especially with treatments like IVF and ICSI.

Caption: This diagram shows three key parts of sperm analysis. In the first section (sperm count), normal sperm count is shown on the left and low sperm count on the right. In the second section (sperm morphology), normal-shaped sperm are on the left and abnormally shaped sperm are on the right. In the third section (sperm motility), normal forward-moving sperm are on the left and sperm with abnormal motility are on the right.

Blastocyst

A blastocyst is an embryo that has developed for about five to six days after fertilisation. At this stage, the embryo has divided into many more cells and formed a fluid-filled cavity, getting ready to implant into the uterine lining.

In IVF, embryos can be transferred at different stages:

• Day 3 embryos: These embryos are typically made up of around 6 to 8 cells. Some clinics may transfer embryos at this stage.
• Day 5 embryos (blastocysts): These embryos have developed further and have a more advanced structure, with over 100 cells.

Dr  Guimarães explains that at Procriar, doctors usually transfer embryos at the blastocyst stage.

“This is because research shows that blastocysts have a higher chance of implanting successfully compared to earlier-stage embryos, as extended culture allows us to know our embryos better.”

This is because embryos that reach the blastocyst stage have already passed important early development milestones, making them more likely to be strong, healthy, and capable of continuing to grow.

Culturing embryos to day 5 also allows the embryology team to select the embryos with the best potential for implantation, giving you the highest possible chance of success.

Caption: This diagram shows a blastocyst, an embryo at day 5 or 6 of development. The inner cell mass (cluster of cells at the bottom) will become the baby. The outer layer of cells, called the trophectoderm, will form the placenta. The fluid-filled space in the centre is the blastocyst cavity. At this stage, embryos are usually transferred in IVF treatment because they have a higher chance of implantation.

Embryo grading

At the blastocyst stage, embryos are often graded using a number and two letters. At Procriar we use both the ASEBIR and the Gardner classifications. For example, you might see a grade like 5AA or 4BB. Here is what this means:

• The number refers to the stage of expansion of the blastocyst (how much it has grown).
• Higher numbers usually indicate a more expanded blastocyst.
• The first letter assesses the quality of the inner cell mass (which will form the baby).
• The second letter assesses the quality of the trophectoderm (which will form the placenta).

Letter grades typically follow this scale:

• A: Excellent quality
• B: Good quality
• C: Fair quality

For example:

• 5AA would be a fully expanded, excellent-quality blastocyst.
• 4BB would be a slightly less expanded but still good-quality blastocyst.
• 3BC would be a less expanded blastocyst with mixed inner cell mass and outer layer quality.

It is important to stress that decisions on embryo transfer and vitrification don’t rely only on these parameters: we always consider aspects like the morphokinetics of the embryo, often assessed with the help of AI tools.

Dr  Guimarães says:

“It is important to remember that embryo grading is a guide, not a guarantee. Even embryos with slightly lower grades can still lead to healthy pregnancies. Your fertility team will explain the grading and help you understand your options.”

Embryo transfer

Embryo transfer happens when one (or sometimes two) embryos are placed into the uterus using a thin catheter. It is a simple procedure, usually takes around 15 to 20 minutes and is relatively painless.

Fresh vs frozen embryo transfer

After IVF, embryos can either be transferred straight away in the same cycle (a fresh transfer) or frozen and transferred later (a frozen embryo transfer, or FET).

Fresh embryo transfer

• A fresh transfer happens a few days after egg retrieval, usually on day 5 of embryo development.
• In some cases, clinics may transfer a day 3 embryo, which is an earlier stage of development with around 6 to 8 cells – at Procriar we don’t transfer at this stage anymore.
• However, during a fresh transfer, your body still carries the effects of the ovarian stimulation medications. Some believe that these hormone levels could affect how receptive the uterine lining is, although many fresh transfers are still very successful.

Frozen embryo transfer (FET)

• In a frozen transfer, embryos are frozen and stored for use in a future cycle.
• Freezing gives your body time to return to a more natural hormonal state, which may create a more balanced environment for implantation.
• FETs also allow more time for additional steps like genetic testing, such as PGT-A (preimplantation genetic testing for aneuploidies), which helps select embryos with the best chance of a healthy pregnancy.

Embryos are often frozen for several reasons, including:

• When we have more viable embryos than the ones that we’re transferring into the womb.
• Completing medical treatments like cancer therapy or managing conditions like endometriosis.
• Planning around the best possible timing for implantation.

Freezing embryos can provide patients with more flexibility and can sometimes improve the chances of a successful pregnancy, depending on individual circumstances.

Natural vs medicated cycle

When preparing for an embryo transfer, there are two main types of cycles:

Natural cycle

• Relies on your body’s natural ovulation.
• No hormone medications are used.
• Your clinic monitors your cycle with ultrasounds and blood tests.
• Transfer is timed based on when you ovulate naturally.
• Best suited for patients with regular periods and reliable ovulation.

Medicated cycle

• Uses hormone medications to prepare the uterus.
• Oestrogen and progesterone help thicken the uterine lining.
• Ovulation and timing are controlled by your doctor.
• Offers more flexibility and planning.
• Often recommended for patients with irregular cycles or previous implantation difficulties.

There are other types of cycle, like the modified natural cycle, that can be used in certain patients. It all depends on the medical assessment of each patient’s unique situation, as at Procriar our decision-making is always personalised.

Implantation

After the embryo transfer, the embryo needs to attach itself to the lining of the uterus. This process is called implantation, and it is one of the most important early steps toward pregnancy.

Implantation usually happens between 6 to 10 days after the embryo transfer.

During this time, the embryo communicates with the endometrium (the inner lining of the uterus), finding the best spot to embed itself.

Once attached, the embryo begins to establish a connection with the mother’s blood supply, allowing it to continue growing.

Several factors can influence successful implantation, including:

• The quality of the embryo
• The thickness and receptivity of the endometrium
• Hormone levels, particularly progesterone
• Overall uterine health

Dr  Guimarães says:

“Implantation is a natural process, and even with perfect conditions, not every embryo will implant. This is why the “two-week wait” after transfer can feel so emotional and uncertain.”

Luteal phase support

After your embryo transfer, you will likely start taking hormone supplements to support implantation and early pregnancy. This is called luteal phase support.

The luteal phase is the second half of your menstrual cycle, the time after ovulation when the body naturally produces progesterone. Progesterone prepares the lining of the uterus to receive an embryo and helps maintain an early pregnancy.

During IVF, hormone levels can sometimes be disrupted due to ovarian stimulation. To make sure the environment stays stable and supportive, additional progesterone (and sometimes estrogen) is prescribed after the transfer.

Luteal phase support can include:

• Vaginal progesterone pessaries, capsules, or gel
• In some cases, oral medications or patches

You will usually continue your luteal support until your pregnancy test, and if you are pregnant, often for the first few weeks of early pregnancy.

These hormone supplements are very important in helping the embryo implant successfully and supporting its early development.

Two-week wait

The two-week wait is the time between your embryo transfer and your pregnancy test. It usually lasts about 9 to 14 days.

During this time, you are waiting to see if implantation has occurred. You might notice symptoms like mild cramping, spotting, or tiredness, but these are not reliable signs of pregnancy, especially if you are taking luteal phase support medication (progesterone can mimic symptoms of early pregnancy).

According to Dr  Guimarães, the two-week wait can be an emotional time, filled with hope and uncertainty.

“Try to be gentle with yourself and trust your clinic’s guidance until your official pregnancy blood test.”

Beta-hCG test

About two weeks after embryo transfer, a blood test will check for the pregnancy hormone (hCG) in your bloodstream. This is often called your “beta test.”

Common IVF procedures

Depending on your situation, your doctor might recommend certain specialised procedures alongside standard IVF. Here are some important ones to know:

Intracytoplasmic sperm injection (ICSI)

ICSI is a laboratory technique where a single sperm is injected directly into an egg to help fertilisation occur. It is often used when there are male fertility issues, such as low sperm count, poor sperm motility, or previous fertilisation difficulties.

Preimplantation genetic testing (PGT)

PGT involves testing embryos for genetic or chromosomal abnormalities before they are transferred. It can be especially useful for couples with a history of genetic conditions, recurrent miscarriages, or previous IVF failures.

There are different types of PGT:

• PGT-A (for aneuploidies): Checks for abnormal numbers of chromosomes.
• PGT-M (for monogenic disorders): Screens for specific inherited diseases.
• PGT-SR (for structural rearrangements): Looks for structural changes in chromosomes.

Egg freezing (oocyte vitrification)

Egg freezing allows women to preserve their fertility by freezing mature eggs for future use. It can be an option for personal reasons, for medical reasons such as cancer treatment, or for those who want to delay starting a family. The eggs are frozen using a fast-freezing method called vitrification, which helps protect them until they are needed.

ROPA method (Reception of Oocytes from Partner)

ROPA is a fertility treatment designed for female same-sex couples. One partner provides the eggs, while the other carries the pregnancy. It allows both partners to share a biological connection to the baby and is a popular choice for many couples seeking a more shared journey to parenthood.

Sperm and egg donation

Sometimes, donor sperm or donor eggs are needed to help achieve a pregnancy.
This may be recommended for individuals or couples facing significant fertility challenges, genetic concerns, or for single parents and same-sex couples. All donors are carefully screened to ensure safety and the best possible outcomes.

Understanding IVF acronyms

You will quickly notice that fertility specialists love acronyms! Here are some of the most common ones explained:

• IVF: In vitro fertilisation
• ICSI: Intracytoplasmic sperm injection
• PGT: Preimplantation genetic testing
• FET: Frozen embryo transfer
• ET: Embryo transfer
• AMH: Anti-Müllerian hormone (a marker of ovarian reserve)
• HCG: Human chorionic gonadotropin (pregnancy hormone)
• TTC: Trying to conceive
• DPT: Days past transfer (used when counting days after embryo transfer)
• OHSS: Ovarian hyperstimulation syndrome (a rare complication of fertility treatment)
• PCOS: Polycystic ovarian syndrome

Understanding these acronyms helps you follow conversations with your medical team more easily.

Why understanding IVF terminology matters

According to Dr  Guimarães:

“Starting IVF is a big emotional, physical, and financial commitment. Feeling confident about what is happening at each stage can reduce anxiety and help you feel more empowered.”

When you understand the words your doctor is using, you can ask better questions, make more informed decisions, and feel like an active participant in your care.

At Procriar, we encourage all our patients to ask questions at every step. No question is too small or too obvious. We believe that informed patients make the strongest decisions.

FAQs about IVF terminology and procedures

What are the most common IVF terms I should know?
Some of the key terms include ovarian stimulation, egg retrieval, fertilisation, embryo transfer, and implantation. Understanding these steps can help you feel more prepared and confident during treatment.

What is the difference between IVF and ICSI?
In standard IVF, eggs and sperm are mixed together and fertilisation happens naturally. In ICSI (intracytoplasmic sperm injection), a single sperm is injected directly into an egg to assist fertilisation, often used when there are male factor fertility issues.

What does PGT mean in IVF?
PGT stands for preimplantation genetic testing. It involves checking embryos for chromosomal abnormalities or monogenic diseases  before they are transferred to the uterus, helping to select the healthiest embryos.

How many embryos are usually transferred during IVF?
In most cases, especially for younger women or when using tested embryos or donor eggs, doctors recommend transferring one embryo to reduce the risk of multiple pregnancies. Your specialist will guide you based on your situation.

What is a frozen embryo transfer (FET)?
A frozen embryo transfer is when an embryo that was previously frozen is thawed and transferred to the uterus in a later cycle. It allows more flexibility in timing and preparation.

Can IVF guarantee a pregnancy?
Unfortunately, no fertility treatment can guarantee a pregnancy. IVF can greatly increase the chances, but success depends on factors like age, embryo quality, and overall health.

Is IVF painful?
The IVF process involves injections, monitoring, and minor procedures. Some women experience mild discomfort, but most find it manageable. Your Procriar team will support you every step of the way.

When should I consider embryo testing (PGT)?
PGT is often recommended if you are over 37 years old, have experienced recurrent miscarriages, have a known genetic condition, or have had repeated IVF failures.

How long does a full IVF cycle take?
A full IVF cycle typically takes around 6 to 8 weeks from the start of ovarian stimulation to the pregnancy test, though timings can vary slightly depending on your personalised treatment plan.

Final thoughts

Understanding IVF terminology and procedures is a powerful step toward feeling more comfortable and in control during your fertility journey.

At Procriar, we are here to guide you with knowledge, experience, and compassion. If you have any questions about IVF or would like to speak with one of our fertility specialists, please get in touch with us today. We are ready to support you every step of the way.