Assisted Reproductive Technology (ART) – Glossary

Aneuploidy: the loss or gain of one or more chromosomes

Assisted Reproduction Technology (ART): all treatments that include in vitro handling of human gametes (eggs and sperm) and embryos to establish a pregnancy – often called MAR (Medically Assisted Reproduction)

Blastocyst: 5-6 days old embryo

Clinical pregnancy: a pregnancy diagnosed by ultrasound of by definite signs of pregnancy

Clone: a copy of a (DNA) molecule, a (stem) cell or an individual. Cloning of an individual is done by replacing the nucleus of an egg cell with the genetic material from a somatic (non-germ) cell. Cloning can also be done to produce stem cells, the undifferentiated early cells from which all types of cells develop. This technique may in future enable people to access life-saving treatments tailored-made from their own DNA.

Cryopreservation: frozen storage of sperm, eggs, embryos or ovarian and testicular tissues

Delivery rate: number of deliveries per 100 cycles (aspiration or embryo transfer cycles)

Ectopic pregnancy: implantation of the embryo outside the uterus

Embryo: the product up to eight weeks after fertilisation, later it is called a foetus

Embryo donation: transfer of an embryo that did not originate from the recipient and her partner

Endometriosis: condition where endometrial tissue grows in areas other than the uterine cavity

FER: frozen embryo replacement

Fertilisation: a sperm penetrates the egg leading to a combination of genetic material resulting in a fertilised egg

Follicle: a fluid filled sac that contains an immature egg. Located in the ovaries, follicles develop each cycle, one ovulates into an egg.

Gamete: a reproductive cell, egg in females and sperm in males

Gamete intra-fallopian transfer (GIFT): process by which eggs and sperm are introduced in the Fallopian tube.

Infertility: a disease of the reproductive system defined by the failure to conceive after 12 months of regular unprotected sexual intercourse

Intracytoplasmic sperm injection (ICSI): process by which an egg is fertilised by injecting a single sperm into the egg

Intrauterine Insemination (IUI): the insemination of washed semen directly into the uterus

In vitro fertilisation (IVF): fertilisation of an egg by sperm in a laboratory dish

Micro-epididymal sperm aspiration (MESA): surgical collection of sperm direct from the epididymis (tube that carries sperm out of the testis). Used when a blockage in the epididymis leads to absence of sperm in the semen.

Miscarriage / preclinical spontaneous abortion: pregnancy diagnosed by the detection of HCG in serum or urine that does not develop into a clinical pregnancy

Percutaneous epididymal sperm aspiration (PESA): collection of sperm under local anaesthesia by needle aspiration of the epididymis.

Polycystic Ovarian Syndrome (PCOS): a condition characterised by irregular or absent menstruation, acne, obesity and excess hair growth

Pre-implantation genetic diagnosis (PGD): diagnostic technique involving genetic tests on an embryo or a polar body (a cell structure inside the egg). Usually done when the embryo is at the 6-8 cell stage. One cell is removed for analysis of its DNA or chromosomes to determine if the embryo is likely to develop a genetic disease.

Pre-implantation genetic screening (PGS): technique to check if an embryo has the correct number of chromosomes. Used particularly for older women (at increased risk of chromosomal abnormalities) and for women who have had recurrent miscarriages (often due to chromosomal abnormalities). It is still in the experimental phase, since it is not yet evidence based.

Single Embryo Transfer (SET): method of selecting one embryo for transfer to lower the risk of multiple pregnancies.

Stillbirth / Fetal death: death of a foetus before it is born at or after 20 weeks of pregnancy

Testicular sperm aspiration (TESA): needle aspiration of the testis to collect sperm, usually carried out in cases where PESA has been unsuccessful.

Testicular sperm extraction (TESE): done when other extraction methods were unsuccessful

Vitrification: an ultra-rapid freezing method for eggs and embryos. It avoids the damage usually caused in freezing from ice crystals.
 

ART fact sheet

Background
•One in six couples worldwide experience some form of infertility problem at least once during their reproductive lifetime. The current prevalence of infertility lasting for at least 12 months is estimated to be around 9% worldwide for women aged 20-44.
•20-30% of infertility cases are explained by physiological causes in men, 20-35% by physiological causes in women, and 25-40% of cases are because of a problem in both partners. In 10-20% no cause is found. Infertility is also associated with lifestyle factors such as smoking, body-weight and stress. Increasing age in the female partner is one of the most common explanations today.
•It is now estimated that around 5 million babies have been born worldwide since the first IVF baby was born in 1978.
•Most ART treatments take place in women aged between 30 and 39.
 

Cycles/treatments
•Europe leads the world in ART, initiating approximately 71% of all reported ART cycles (not including Asia).
•In 2009, the latest year for which figures are available, 537,287 treatment cycles were reported from 33 European countries. This compares globally (in 2007) with 142,435 cycles from the US and 56,817 cycles from Australia and New Zealand. The number of cycles performed in many developed countries has grown by 5-10% per annum over the last few years, but that growth is now showing signs of slowing.
•In 2009 France (74,767 cycles), Germany (68,041), Spain (54,266), the UK (54,314) and Italy (52,032) were Europe's most active countries. In the Nordic countries, Sweden leads the table with 16,743 cycles, followed by Denmark (14,002).
•The most active countries in the world are the USA and Japan.

Availability of ART
•The Nordic countries and Belgium have the highest ART availability in terms of cycles per million population.
•In Belgium, Slovenia, Denmark, Netherlands and Sweden more than 3.0% of all babies born were conceived by ART. By contrast the proportion in the USA - with 57,569 ART babies born - was estimated to be slightly more than 1% of total births.
•Around 1.5 million ART cycles are performed each year worldwide, with an estimated 350,000 babies born.
 

Pregnancies and delivery rates
•An analysis of world data for 2007 put average delivery rate from ART treatment at 21.7% per aspiration and 27% cumulative from a single started treatment cycle.
•Large differences exist between countries in the number of embryos transferred and resulting multiple births. However, there is a consistent trend towards transfer of fewer embryos. The overall average number is 2.14 embryos per transfer.
•In Europe the multiple delivery rate per embryo transfer has declined steadily since 2000 from 26.9% to 21.8% in 2007 compared to a multiple delivery rate of 33% in the US (29% twin, 4% triplet or more deliveries).
•Sweden has the lowest multiple delivery rate in the world. In 69.9% of all cases a single embryo was transferred.
•In Europe in 2009 the mean pregnancy rate per embryo transfer was 32.8% after IVF, 32 % after ICSI, 22.5% after frozen embryo transfer and 42.2% after egg donation. Rates are higher in younger (<35 years) patients.
 

Treatments
•The most common fertilisation (treatment) technique is ICSI. Overall, ICSI accounts for around two-thirds of all treatments worldwide, and conventional IVF around one-third. However, these proportions vary greatly between countries, even though outcome rates with each technique are comparable.
•Success rates from frozen embryo transfer are increasing, as are the number of FER cycles. Vitrification, as an efficient cryopreservation technique, has improved the outcome of both embryo and oocyte freezing.
•Ovarian hyperstimulation syndrome (OHSS) is a complication related to ART. In 2008 there were 2470 OHSS cases recorded in 24 out of 33 European countries reporting to ESHRE, making up 0.5% of cycles. UK (641), Russia (483) and Italy (212) reported the highest number of patients with OHSS.

 

Assisted reproductive technology and intrauterine inseminations in Europe, 2009: results generated from European registers by ESHRE, presented at 2012 annual meeting of ESHRE, Istanbul,

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC), Assisted Reproduction Technology Success Rates (2007), National Summary and Fertility Clinic Reports, December 2009 at http://www.cdc.gov/art/ART2007/PDF/COMPLETE_2007_ART.pdf

AIHW (2008) Australian Institute of Health and Welfare, Assisted Reproduction Technology in Australia and New Zealand 2007. National Perinatal Statistical Unit and Fertility Society of Australia. Assisted Reproduction Technology Series, number 13, at http://www.aihw.gov.au/publications/index.cfm/title/10598
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