Glossary of IVF Terminology

IVF TerminologyCentral IVF's glossary of IVF terminology brings you a list of some of the common terms you might encounter during your treatment.

  • Antagonist Injection

The antagonist injection is performed on a daily basis during 1-4 days preceding the trigger injection in order to suppress ovulation until the follicles have matured. It is given alongside the FSH injections.

  • Artificial Frozen-Thawed Embryo Transfer Cycle (FET)

Cycle controlled using hormone replacement treatment (estrogen and progesterone).

  • Blood Tests

If indicated by our fertility specialist, blood tests may be scheduled throughout an IVF cycle to check hormone levels.

  • Controlled Ovarian Stimulation Cycle using GnRH Antagonist

Day 1 – Call our Nursing Team. Our nurses will provide you with instructions on starting the Follicle Stimulating Hormone (FSH) injections, which will typically commence on day 3 of your cycle. You will be advised as to the dosages and the dates to book your first stimulation scan for.

  • Egg Donation

Egg donation (also known as oocyte or ovum donation) is a form of fertility treatment where a young, healthy woman's eggs are collected and subsequently used to produce embryos that are then transferred to a recipient's uterus with the hope of achieving a pregnancy.

  • Egg (Oocyte) Retrieval

A short procedure (generally lasting no longer than 30 minutes) conducted on an outpatient basis. Central IVF fertility specialist will specify the possible dates for administering the trigger injection with egg retrieval scheduled to take place approximately 35-37 hours later.
During the latter procedure, which is held at our outpatient clinic under sedation, an ultrasound probe equipped with a fine needle is introduced into the vagina to conduct follicular aspiration. The test tubes containing the aspirated fluid are then sent to a lab where our embryologist studies the fluid to locate any available eggs.

  • Embryo Transfer

A procedure performed by one of our fertility specialists at our clinic. Typically sedation is not required. Just like during a PAP smear, a speculum is inserted into the vagina. Once the cervix is visible, a narrow soft tube called a catheter is gently passed through the opening of the cervix.

The embryo is then introduced into the uterus. The procedure takes only a few minutes and is usually associated with minimal discomfort. Your husband/partner may stay with you during the procedure.

On the evening of the embryo transfer, patients will typically start taking their progesterone medication (for at least 2 weeks) to ensure the lining of the uterus is prepared for embryo implantation.

  • Fertilization & Embryo Development

The embryos are "cultured" under the tight supervision of the embryologists for two to five days until the date the embryo transfer is scheduled for.

  • FSH (Follicle-stimulation Hormone)

A gonadotropin, which regulates the reproductive cycle and stimulates the growth of follicles in the ovaries.

  • Follicle Tracking Scan

A transvaginal US scan performed to assess and measure the following: endometrial thickness and the number of follicles in both ovaries.

  • GnRH Antagonist (Gonadotropin-releasing Hormone Antagonist)

A receptor blocker drug, which is designed to prevent the release of LH and FSH from the pituitary gland. When used as part of fertility treatments it is typically given following the administration of hCG.

  • Pregnancy Test

Pregnancy tests are scheduled 11 to 14 days following the embryo transfer. In case of a positive result an ultrasound scan is arranged to verify the results and confirm the viability of the pregnancy. Depending on circumstances you may be required to undergo a series of additional blood tests in order to monitor the progress of your pregnancy hormone levels prior to the US scan.

  • Progesterone Therapy

Progesterone is a hormone, which prepares the uterine lining for the upcoming implantation. Both estrogen and progesterone should be continued up until the pregnancy test including the morning of  the embryo transfer.

It is important to note that prior to the pregnancy test (due to the medication you will be taking) no menstrual bleeding is normally expected. If you do experience any bleeding please contact your nursing team.

  • Role of Male Partner (If using Fresh Sperm):

On the day of the trigger injection (2 days prior to egg retrieval) your partner will be asked to produce an ejaculate and abstain until the egg retrieval procedure, at which time he will be required to provide a fresh sperm sample.

Some couples may wish to freeze and store sperm for potential use. This can be discussed with our fertility specialist prior to commencing the cycle.

  • Stimulation Scan and Blood Test

An ultrasound scan, which takes place around day 6-8 of the cycle to determine if you are ready to start the second series of injections, called the antagonist injections.

  • Trigger Injection

Once you have an optimal number and size of mature follicles (determined by the stimulation scan) you are ready for the trigger injection (aka "trigger shot") of hCG (Human Chorionic Gonadotrophin) to induce the final maturation of oocytes. Egg retrieval takes place approximately 36 hours later.

  • Ultrasound Scan

The scan will be performed on Day 12 of your cycle to examine and assess the lining of the uterus and its condition. Once the uterine lining is confirmed to have reached sufficient thickness, you will be cleared for admission to our clinic. You will commence progesterone pessaries / vaginal tablets when advised.


An egg donor will become available to donate only after their screening is complete and our donor team has designated them as eligible...

Quality Management System

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