Definitions

American Society for Reproductive Medicine

The American Society for Reproductive Medicine, commonly referred to as ASRM, is a professional medical organization composed of more than 8,000 healthcare professionals dedicated to the advancement of reproductive medicine. ASRM provides clinical guidance, education, research, and professional standards related to infertility and reproductive health.

Aneuploidy

Aneuploidy refers to an abnormal number of chromosomes in a cell. In reproductive medicine, embryos that are uniformly aneuploid are generally not compatible with successful development or establishment of a viable pregnancy. Such embryos are commonly referred to as aneuploid embryos.

Cryopreservation

Cryopreservation is the process of preserving biological material at extremely low temperatures. In fertility care, this may include gametes, zygotes, cleavage-stage embryos, morulae, blastocysts, or gonadal tissue. Cryopreservation is typically performed through vitrification or slow-freezing techniques.

Diploidy

Diploidy is the chromosomally normal state in humans in which cells contain two copies of each of the 22 autosomes, as well as a pair of sex chromosomes. Diploidy is considered the normal chromosomal condition for most human cells.

Embryo

An embryo is a fertilized egg that has begun cell division. In assisted reproductive technology, embryo development is closely monitored before transfer, cryopreservation, or genetic testing.

Embryo Transfer

Embryo transfer is the procedure of placing one or more preimplantation embryos into the uterus. Embryos may be transferred at different developmental stages, generally from day 1 through day 7. Although embryos from day 1 to day 3 can also be transferred into the fallopian tube, this is rarely indicated in current practice.

Endometrial Receptivity Test

An endometrial receptivity test, often referred to as an endometrial receptivity assay or ERA, is a diagnostic biopsy of the uterus. The purpose of the test is to help identify the window of progesterone exposure most favorable for embryo implantation.

Euploidy

Euploidy is the condition in which a cell has chromosomes in an exact multiple of the haploid number. In humans, this multiple is normally two. A chromosomally normal embryo is considered euploid and is also diploid.

Failed Implantation

Failed implantation refers to the absence of evidence of pregnancy following embryo transfer. This may include the absence of a positive pregnancy test and/or the absence of a gestational sac on ultrasound after transfer.

Gonadotropins

Gonadotropins are naturally occurring hormones that include follicle-stimulating hormone, luteinizing hormone, and human chorionic gonadotropin. These hormones are produced in the human body and are also available as injectable medications. In female patients, they may be used to induce ovulation or stimulate the development of multiple eggs. In male patients, they may sometimes be used to support sperm production.

Intrauterine Insemination

Intrauterine insemination, or IUI, is a fertility procedure in which laboratory-processed sperm are placed directly into the uterus in an attempt to achieve pregnancy.

In Vitro Fertilization

In vitro fertilization, or IVF, is a sequence of procedures involving fertilization of gametes outside the body. IVF may include ovarian stimulation, egg retrieval, fertilization, embryo culture, embryo transfer, cryopreservation, and, in some cases, genetic testing.

MII / Metaphase II Oocyte

MII, or metaphase II, is the stage of oocyte maturation in which the oocyte has completed meiosis I and has entered the second meiotic division. This stage is clinically important because metaphase II oocytes are considered mature and capable of fertilization.

Mock Cycle

A mock cycle, or endometrial receptivity analysis cycle, is performed in a manner similar to preparation for a frozen embryo transfer. However, instead of transferring an embryo, an endometrial biopsy is performed. The biopsy is used to assess whether the uterine lining would likely have been receptive at the time an embryo transfer would have occurred.

Oocyte

An oocyte is the medical term for an egg, or female gamete. It may also be referred to as an ovum in the singular form or ova in the plural form.

Preimplantation Genetic Testing

Preimplantation genetic testing, or PGT, is testing performed on cells removed from an embryo. These cells are screened for genetic abnormalities. PGT may be performed in conjunction with IVF and may include different types of genetic testing depending on the clinical indication.

Society for Assisted Reproductive Technology

The Society for Assisted Reproductive Technology, or SART, is a society affiliated with ASRM. It is composed of representatives from assisted reproductive technology programs that have demonstrated the ability to perform IVF.

Zygote

A zygote is a fertilized egg before cell division, or cleavage, begins.