Human Reproduction, Vol.24, No.11 pp.

2683–2687, 2009
Advanced Access publication on October 4, 2009 doi:10.1093/humrep/dep343

SIMULTANEOUS PUBLICATION Infertility

The International Committee for

Monitoring Assisted Reproductive
Technology (ICMART) and the World
Health Organization (WHO) Revised
Glossary on ART Terminology, 2009†
F. Zegers-Hochschild 1,9, G.D. Adamson 2, J. de Mouzon 3, O. Ishihara4,
R. Mansour 5, K. Nygren 6, E. Sullivan 7, and S. van der Poel 8 on behalf of
ICMART and WHO
1
Unit of Reproductive Medicine, Clinicas las Condes, Santiago, Chile 2Fertility Physicians of Northern California, Palo Alto and San Jose,
California, USA 3INSERM U822, Hôpital de Bicêtre, Le Kremlin Bicêtre Cedex, Paris, France 4Saitama Medical University Hospital,
Moroyama, Saitana 350-0495, JAPAN 53 Rd 161 Maadi, Cairo 11431, Egypt 6IVF Unit, Sophiahemmet Hospital, Stockholm, Sweden
7
Perinatal and Reproductive Epidemiology and Research Unit, School Women’s and Children’s Health, University of New South Wales,
Sydney, Australia 8Department of Reproductive Health and Research, and the Special Program of Research, Development and Research
Training in Human Reproduction, World Health Organization, Geneva, Switzerland
9
Correspondence address: Unit of Reproductive Medicine, Clinica las Condes, Lo Fontecilla, 441, Santiago, Chile. Fax: 56-2-6108167,
E-mail: fzegers@clc.cl

background: Many definitions used in medically assisted reproduction (MAR) vary in different settings, making it difficult to standardize
and compare procedures in different countries and regions. With the expansion of infertility interventions worldwide, including lower
resource settings, the importance and value of a common nomenclature is critical. The objective is to develop an internationally accepted
and continually updated set of definitions, which would be utilized to standardize and harmonize international data collection, and to assist in
monitoring the availability, efficacy, and safety of assisted reproductive technology (ART) being practiced worldwide.
method: Seventy-two clinicians, basic scientists, epidemiologists and social scientists gathered together at the WHO headquarters in
Geneva, Switzerland in December, 2008. Several months in advance, three working groups were established which were responsible for termi-
nology in three specific areas: clinical conditions and procedures, laboratory procedures and outcome measures. Each group reviewed the exist-
ing ICMART glossary, made recommendations for revisions and introduced new terms to be considered for glossary expansion.
results: A consensus was reached on 87 terms, expanding the original glossary by 34 terms, which included definitions for numerous clinical
and laboratory procedures. Special emphasis was placed in describing outcome measures such as cumulative delivery rates and other markers of
safety and efficacy in ART.
conclusions: Standardized terminology should assist in analysis of worldwide trends in MAR interventions and in the comparison of ART
outcomes across countries and regions. This glossary will contribute to a more standardized communication among professionals responsible for
ART practice, as well as those responsible for national, regional and international registries.

over measures of efficacy and safety have generated both scientific and
Introduction public interest (GD Adamson et al, 2006; J de Mouzon et al, 2004; RP
The need for standard definitions is critical for benchmarking the out- Dickey, 2007; European IVF Monitoring Consortium Report, ESHRE,
comes of assisted reproductive technology (ART) procedures, at both 2008). Definitions used in medically assisted reproduction within
a national and international level. Increase in the use of ART treatment different countries are frequently the result of adaptations to particular
worldwide and the continuing discussions, controversies and debates medical, cultural and religious settings. However, when undertaking

†
This glossary is simultaneously published in Fertility and Sterility (Volume 92, No 5)

& World Health Organization [2009]. All rights reserved. The World Health Organization has granted Oxford University Press permission for the reproduction of this article

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international data collection, standardization is necessary so that moni- Working methodology

toring of efficacy, safety and quality of procedures and multinational
research can be undertaken. This revised and enhanced version of the ICMART glossary is the
The International Committee for Monitoring Assisted Reproductive result of discussion and consensus reached among seventy-two (72)
Technology (ICMART), an entity responsible for the collection and clinicians, basic scientists, epidemiologists and social scientists gathered
dissemination of worldwide data on ART, published the first glossary together at the WHO headquarters in Geneva, Switzerland from
on ART terminology in 2006 (Zegers-Hochschild, 2006, Fertil Steril; December 1-5, 2008. Three working groups were established
Zegers-Hochschild, 2006, Hum Reprod.). That particular glossary several months in advance. Each working group was responsible for
resulted from discussions by participants at an international meeting reviewing the existing glossary and recommending new terminologies
on “Medical, Ethical and Social Aspects of Assisted Reproduction” to represent clinical, laboratory and outcome measures.
organized by the WHO in 2001 (ICMART, The ICMART glossary, The professionals facilitating each working group, in alphabetical
Report of a WHO meeting, 2002). order, were:
In December 2008, the WHO with the assistance of the ICMART, Clinical: David Adamson, Thomas D’Hooghe, Osamu Ishihara,
the Low Cost IVF Foundation (LCIVFF) and the International Federa- Fernando Zegers-Hochschild.
tion of Fertility Societies (IFFS), organized an international WHO Laboratory: Trevor Cooper, Outi Hovatta, Arne Sunde, Alan
meeting on “Assisted Reproductive Technologies: Common Terminol- Trounson.
ogy and Management in Low-Resource Settings”. ICMART members Outcome: Maryse Bonduelle, Jacques de Mouzon, Orvar Finnström,
and the WHO were responsible for steering an extensive review Hassan Sallam.
and improvement of the already existing “Glossary on ART Terminol- Each term, with its definition, was presented by the appropriate
ogy” (Zegers-Hochschild, 2006, Fertil Steril; Zegers-Hochschild, 2006, working group to all participants within sessions of the 2008
Hum Reprod). They were guided by the objective of developing an meeting at the WHO. The final version of this glossary was generated
internationally accepted set of definitions that would help standardize by meeting participants following thorough discussion, review of
and harmonize international data collection to monitor the availability, new and existing definitions, as well as opportunities throughout
efficacy, and safety of ART interventions to achieve high quality data in the week to engage the working groups for clarifications and
all settings including low-resource settings. suggestions before a final consensus on each term and definition
The WHO, in collaboration with the organizing committee, gath- was realized.
ered health professionals from developed and developing countries, We anticipate this glossary will contribute to a more fluid communi-
who were selected for their expertise and/or as representatives of cation among professionals responsible for ART practice, as well as
major international and national reproductive health medical organiz- those responsible for national, regional and international registries of
ations, including the American Society for Reproductive Medicine ART data. Standardized terminology should assist analysis of world-
(ASRM), the European Society for Human Reproduction and Embry- wide trends and in the comparison of outcomes across countries
ology (ESHRE), the International Committee for Monitoring Assisted and regions. This glossary does not include specific measures of
Reproductive Technology (ICMART), the Red Latino Americana de “success” which would take into consideration the well-being of
Reproducción Asistida (RED), the International Federation of Fertility babies as well as of their mothers, fathers, surrogates and/or
Societies (IFFS), the International Federation of Gynaecology and gamete donors.
Obstetrics (FIGO), the Middle East Fertility Society (MEFS), the
Japan Society for Reproductive Medicine (JSRM), the Japan Society
for Obstetrics and Gynaecology (JSOG), the Society of Obstetrics
and Gynaecology of Burkina (SOGOB), the Chinese Society of Repro- Acknowledgements
ductive Medicine, the Indian Society for Assisted Reproduction, the
Brazilian Society of Assisted Reproduction (SBRA), the World Endo- ICMART currently receives funding from the American Society for
metriosis Society (WES), the Fertility Society of Australia (FSA), the Reproductive Medicine (ASRM), the Society for Assisted Reproductive
International Society for Mild Approaches to Assisted Reproduction Technology (SART), the European Society for Human Reproduction
(ISMAAR), the Russian Association of Human Reproduction and Embryology (ESHRE), the Fertility Society of Australia (FSA),
(RAHR), the Asia Pacific Initiative on Reproduction (ASPIRE), and The Latin American Network of Assisted Reproduction (RED), the
the Low Cost IVF Foundation (LCIVFF), as well as the editors of the Japan Fertility Society (JFS), and the Middle East Fertility Society
journals Fertility and Sterility and Human Reproduction. (MEFS).

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 The International Committee for Monitoring Assisted Reproductive Technology 2685

Glossary total number of embryos fresh and/or frozen/thawed have been

utilized from one ART cycles. Note: The delivery of a singleton, twin
Assisted hatching: an in vitro procedure in which the zona pellucida or other multiple pregnancy is registered as one delivery.
of an embryo is either thinned or perforated by chemical, mechan-
Delivery: the expulsion or extraction of one or more fetuses from
ical or laser methods to assist separation of the blastocyst.
the mother after 20 completed weeks of gestational age.
Assisted reproductive technology (ART): all treatments or
Delivery rate after ART treatment per patient: the number of
procedures that include the in vitro handling of both human
deliveries with at least one live born baby per patient following a
oocytes and sperm, or embryos, for the purpose of establishing a
specified number of ART treatments.
pregnancy. This includes, but is not limited to, in vitro fertilization
and embryo transfer, gamete intrafallopian transfer, zygote Delivery rate: the number of deliveries expressed per 100 initiated
intrafallopian transfer, tubal embryo transfer, gamete and embryo cycles, aspiration cycles or embryo transfer cycles. When delivery
cryopreservation, oocyte and embryo donation, and gestational rates are given, the denominator (initiated, aspirated or embryo
surrogacy. ART does not include assisted insemination (artificial transfer cycles) must be specified. It includes deliveries that resulted
insemination) using sperm from either a woman’s partner or a in the birth of one or more live babies and/or stillborn babies. Note:
sperm donor. The delivery of a singleton, twin or other multiple pregnancy is registered
as one delivery.
Biochemical pregnancy (preclinical spontaneous abortion/
miscarriage): a pregnancy diagnosed only by the detection of Early neonatal death: death of a live born baby within 7 days of
HCG in serum or urine and that does not develop into a clinical birth.
pregnancy. Ectopic pregnancy: a pregnancy in which implantation takes place
Blastocyst: an embryo, five or six days after fertilization, with an outside the uterine cavity.
inner cell mass, outer layer of trophectoderm and a fluid-filled Elective embryo transfer: the transfer of one or more embryos,
blastocoele cavity. selected from a larger cohort of available embryos.
Cancelled cycle: an ART cycle in which ovarian stimulation or moni- Embryo: the product of the division of the zygote to the end of the
toring has been carried out with the intention to treat, but did not embryonic stage, eight weeks after fertilization. (This definition does
proceed to follicular aspiration or, in the case of a thawed embryo, not include either parthenotes - generated through parthenogenesis
to embryo transfer. - nor products of somatic cell nuclear transfer.)
Clinical pregnancy: a pregnancy diagnosed by ultrasonographic Embryo donation: the transfer of an embryo resulting from gametes
visualization of one or more gestational sacs or definitive clinical (spermatozoa and oocytes) that did not originate from the recipient
signs of pregnancy. It includes ectopic pregnancy. Note: Multiple and her partner.
gestational sacs are counted as one clinical pregnancy. Embryo recipient cycle: an ART cycle in which a woman receives
Clinical pregnancy rate: the number of clinical pregnancies zygote(s) or embryo(s) from donor(s).
expressed per 100 initiated cycles, aspiration cycles or embryo trans- Embryo/fetus reduction: a procedure to reduce the number of
fer cycles. Note: When clinical pregnancy rates are given, the denominator viable embryos or fetuses in a multiple pregnancy.
(initiated, aspirated or embryo transfer cycles) must be specified.
Embryo transfer (ET): the procedure in which one or more
Clinical pregnancy with fetal heart beat: pregnancy diagnosed embryos are placed in the uterus or Fallopian tube.
by ultrasonographic or clinical documentation of at least one fetus
Embryo transfer cycle: an ART cycle in which one or more
with heart beat. It includes ectopic pregnancy.
embryos are transferred into the uterus or Fallopian tube.
Congenital anomalies: all structural, functional, and genetic
Extremely low birth weight: birth weight less than 1,000 grams.
anomalies diagnosed in aborted fetuses, at birth or in the neonatal
period. Extremely preterm birth: a live birth or stillbirth that takes place
after at least 20 but less than 28 completed weeks of gestational
Controlled ovarian stimulation (COS) for ART: pharmacologi-
age.
cal treatment in which women are stimulated to induce the devel-
opment of multiple ovarian follicles to obtain multiple oocytes at Fertilization: the penetration of the ovum by the spermatozoon and
follicular aspiration. combination of their genetic material resulting in the formation of a
zygote.
Controlled ovarian stimulation (COS) for non-ART cycles:
pharmacological treatment for women in which the ovaries are Fetal death (stillbirth): death prior to the complete expulsion or
stimulated to ovulate more than one oocyte. extraction from its mother of a product of fertilization, at or after
20 completed weeks of gestational age. The death is indicated by
Cryopreservation: the freezing or vitrification and storage of
the fact that, after such separation, the fetus does not breathe or
gametes, zygotes, embryos or gonadal tissue.
show any other evidence of life such as heart beat, umbilical cord
Cumulative delivery rate with at least one live born baby: the pulsation, or definite movement of voluntary muscles.
estimated number of deliveries with at least one live born baby
Fetus: the product of fertilization from completion of embryonic
resulting from one initiated or aspirated ART cycle including the
development, at eight completed weeks after fertilization, until
cycle when fresh embryos are transferred, and subsequent
abortion or birth.
frozen/thawed ART cycles. This rate is used when less than the

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Frozen/thawed embryo transfer cycle (FET): an ART pro- definite movement of voluntary muscles, irrespective of whether
cedure in which cycle monitoring is carried out with the intention the umbilical cord has been cut or the placenta is attached.
of transferring a frozen/thawed embryo or frozen/thawed Live birth delivery rate: the number of deliveries that resulted in at
embryos. Note: A FET cycle is initiated when specific medication is pro- least one live born baby expressed per 100 initiated cycles, aspira-
vided or cycle monitoring is started with the intention to treat. tion cycles or embryo transfer cycles. When delivery rates are given,
Frozen/thawed oocyte cycle: an ART procedure in which cycle the denominator (initiated, aspirated, or embryo transfer cycles)
monitoring is carried out with the intention of fertilizing thawed must be specified.
oocytes and performing embryo transfer. Low birth weight: Birth weight less than 2,500 grams.
Full-term birth: a live birth or stillbirth that takes place between 37 Medically Assisted Reproduction (MAR): reproduction brought
completed and 42 completed weeks of gestational age. about through ovulation induction, controlled ovarian stimulation,
Gamete intrafallopian transfer (GIFT): an ART procedure in ovulation triggering, ART procedures, and intrauterine, intracervical,
which both gametes (oocytes and spermatozoa) are transferred and intravaginal insemination with semen of husband/partner or
to the Fallopian tubes. donor.
Gestational age: age of an embryo or fetus calculated by adding 2 MESA: Microsurgical Epididymal Sperm Aspiration.
weeks (14 days) to the number of completed weeks since fertiliza- MESE: Microsurgical Epididymal Sperm Extraction.
tion. Note: For frozen/thawed embryo transfers, an estimated date of
Micromanipulation: a technology that allows micro-operative pro-
fertilization is computed by subtracting the embryo age at freezing
cedures to be performed on the spermatozoon, oocyte, zygote or
from the transfer date of the FET cycle.
embryo.
Gestational carrier (surrogate): a woman who carries a preg-
MicroTESE: Microsurgical Testicular Sperm Extraction.
nancy with an agreement that she will give the offspring to the
intended parent(s). Gametes can originate from the intended Mild ovarian stimulation for IVF: a procedure in which the
parent(s) and/or a third party (or parties). ovaries are stimulated with either gonadotropins and/or other
compounds, with the intent to limit the number of oocytes obtained
Gestational sac: a fluid-filled structure associated with early preg-
for IVF to fewer than seven.
nancy, which may be located inside or outside the uterus (in case
of an ectopic pregnancy). Missed abortion: a clinical abortion where the embryo(s) or
fetus(es) is/are non-viable and is/are not expelled spontaneously
Hatching: the process by which an embryo at the blastocyst stage
from the uterus.
separates from the zona pellucida.
Modified natural cycle: an IVF procedure in which one or more
High-order multiple: a pregnancy or delivery with three or more
oocytes are collected from the ovaries during a spontaneous men-
fetuses or neonates.
strual cycle. Drugs are administered with the sole purpose of block-
Implantation: the attachment and subsequent penetration by the ing the spontaneous LH surge and/or inducing final oocyte
zona-free blastocyst (usually in the endometrium) that starts five maturation.
to seven days after fertilization.
Multiple gestation/birth: a pregnancy/delivery with more than one
Implantation rate: the number of gestational sacs observed, divided fetus/neonate.
by the number of embryos transferred.
Natural cycle IVF: an IVF procedure in which one or more oocytes
In vitro fertilization (IVF): an ART procedure that involves extra- are collected from the ovaries during a spontaneous menstrual cycle
corporeal fertilization. without any drug use.
Induced abortion: the termination of a clinical pregnancy, by delib- Neonatal death: death of a live born baby within 28 days of birth.
erate interference that takes place before 20 completed weeks of
Neonatal period: the time interval that commences at birth and
gestational age (18 weeks post fertilization) or, if gestational age is
ends 28 completed days after birth.
unknown, of an embryo/fetus of less than 400 grams.
Oocyte donation cycle: a cycle in which oocytes are collected from
Infertility (clinical definition): a disease of the reproductive
a donor for clinical application or research.
system defined by the failure to achieve a clinical pregnancy after
12 months or more of regular unprotected sexual intercourse. Oocyte recipient cycle: an ART cycle in which a woman receives
oocytes from a donor.
Initiated cycle: an ART cycle in which the woman receives specific
medication for ovarian stimulation, or monitoring in the case of Ovarian Hyper Stimulation Syndrome (OHSS): an exaggerated
natural cycles, with the intention to treat, irrespective of whether systemic response to ovarian stimulation characterized by a wide
or not follicular aspiration is attempted. spectrum of clinical and laboratory manifestations. It is classified
as mild, moderate or severe according to the degree of abdominal
IntraCytoplasmic Sperm Injection (ICSI): a procedure in which
distention, ovarian enlargement and respiratory, haemodynamic and
a single spermatozoon is injected into the oocyte cytoplasm.
metabolic complications.
Live birth: the complete expulsion or extraction from its mother of a
Ovarian torsion: the partial or complete rotation of the ovarian vas-
product of fertilization, irrespective of the duration of the preg-
cular pedicle that causes obstruction to ovarian blood flow, poten-
nancy, which, after such separation, breathes or shows any other
tially leading to necrosis of ovarian tissue.
evidence of life such as heart beat, umbilical cord pulsation, or

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Ovulation Induction (OI): pharmacological treatment of women Vanishing sac(s) or embryo(s): spontaneous disappearance of one
with anovulation or oligo-ovulation with the intention of inducing or more gestational sacs or embryos in an ongoing pregnancy, docu-
normal ovulatory cycles. mented by ultrasound.
Perinatal mortality: fetal or neonatal death occurring during late Very low birth weight: Birth weight less than 1,500 grams.
pregnancy (at 20 completed weeks of gestational age and later), Very preterm birth: a live birth or stillbirth that takes place after at
during childbirth and up to 7 completed days after birth. least 20 but less than 32 completed weeks of gestational age.
PESA: Percutaneous Epididymal Sperm Aspiration. Vitrification: an ultra-rapid cryopreservation method that prevents
Post-term birth: a live birth or stillbirth that takes place after 42 ice formation within the suspension which is converted to a glass-
completed weeks of gestational age. like solid.
Preimplantation Genetic Diagnosis (PGD): analysis of polar Zygote: a diploid cell resulting from the fertilization of an oocyte by a
bodies, blastomeres or trophectoderm from oocytes, zygotes or spermatozoon, which subsequently divides to form an embryo.
embryos for the detection of specific genetic, structural and/or Zygote Intra-Fallopian Transfer (ZIFT): a procedure in which
chromosomal alterations. zygote(s) is/are transferred into the Fallopian tube.
Preimplantation Genetic Screening (PGS): analysis of polar
bodies, blastomeres or trophectoderm from oocytes, zygotes or
embryos for the detection of aneuploidy, mutation and/or DNA References
rearrangement. International Committee for Monitoring Assisted Reproductive
Preterm birth: a live birth or stillbirth that takes place after at least Technology (ICMART): Adamson G.D., de Mouzon J., Lancaster P.,
20 but before 37 completed weeks of gestational age. Nygren K.G., Sullivan E., Zegers-Hochschild F. World Collaborative
Report on in-vitro Fertilization, 2000. Fertil Steril 2006, 85(6);
Recurrent spontaneous abortion/miscarriage: the spontaneous
1586 – 1622.
loss of two or more clinical pregnancies. International Committee for Monitoring Assisted Reproductive
Reproductive surgery: surgical procedures performed to diagnose, Technology, de Mouzon J., Lancaster P., Nygren K.G., Sullivan E.,
conserve, correct and/or improve reproductive function. Zegers-Hochschild F., Mansour R., Ishihara O., Adamson D. World
Collaborative Report on in-vitro Fertilization, 2004. Hum Reprod 2009,
Severe Ovarian Hyper Stimulation Syndrome: severe OHSS is
in press.
defined to occur when hospitalization is indicated. (see definition of
Dickey R.P. The relative contribution of assisted reproductive technologies
Ovarian Hyper Stimulation Syndrome) and ovulation induction to multiple births in the United States 5 years
Small for gestational age: birth weight less than 2 standard devi- after the Society for Assisted Reproductive Technology/American
ations below the mean or less than the 10th centile according to Society for Reproductive Medicine recommendation to limit the
local intrauterine growth charts. number of embryos transferred. Fertil Steril 2007, 88 (6); 1554 –1561.
The European IVF-monitoring (EIM) Consortium, European Society of
Sperm recipient cycle: an ART cycle in which a woman
Human Reproduction and Embryology (ESHRE). Assisted reproductive
receives spermatozoa from a donor who is someone other than technology in Europe, 2004: results generated from European
her partner. registers by ESHRE. Hum Reprod 2008, 23; 756 – 771.
Spontaneous abortion/miscarriage: the spontaneous loss of a Zegers-Hochschild F., Nygren K.G., Adamson G.D., de Mouzon J.,
clinical pregnancy that occurs before 20 completed weeks of gesta- Lancaster P., Mansour R., Sullivan E. on behalf of the International
tional age (18 weeks post fertilization) or, if gestational age is Committee Monitoring Assisted Reproductive Technologies
unknown, the loss of an embryo/fetus of less than 400 grams. (ICMART). The International Committee Monitoring Assisted
Reproductive Technologies (ICMART) Glossary on ART Terminology.
TESA: Testicular Sperm Aspiration. Fertil Steril 2006, 86 (1); 16 – 19.
TESE: Testicular Sperm Extraction. Zegers-Hochschild F., Nygren K.G., Adamson G.D., de Mouzon J.,
Lancaster P., Mansour R., Sullivan E. on behalf of the International
Total delivery rate with at least one live birth: the estimated
Committee Monitoring Assisted Reproductive Technologies. The
total number of deliveries with at least one live born baby resulting
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one ART cycles. Note: The delivery of a singleton, twin or other multiple controversies in assisted reproduction. Report of a WHO meeting. Geneva,
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