GLOSSARY
The International Glossary on Infertility and Fertility Care
The following glossary was developed in 2017 by a global panel of more than 100 multidisciplinary experts, professional organisations, and patient representatives to provide consensus agreement on 283 items and definitions. Published in Fertility and Sterility (FNS) and Human Reproduction (HR).
A printable version of the 2017 Glossary and more information on the methodology, and a list of previous compiled glossaries can be found here.
Natural cycle ART
An ART procedure in which one or more oocytes are collected from the ovaries during a menstrual cycle without the use of any pharmacological compound.
Necrozoospermia
The description of an ejaculate in which no live spermatozoa can be found.
Neonatal death/mortality
Death of a live born baby within 28 days of birth. This can be sub-divided into a) early, if death occurs in the first 7 days after birth; and b) late, if death occurs between 8 and 28 days after birth.
Neonatal mortality rate
Number of neonatal deaths (up to 28 days) per 1000 live births.
Neonatal period
The period which commences at birth and ends at 28 completed days after birth.
Non-obstructive azoospermia
Absence of spermatozoa in the ejaculate due to lack of production of mature spermatozoa.
Nuclear maturation
The process during which the oocyte resumes meiosis and progresses from prophase I to metaphase II.
Obstructive azoospermia
Absence of spermatozoa in the ejaculate due to occlusion of the ductal system.
Oligospermia
A term for low semen volume now replaced by hypospermia to avoid confusion with oligozoospermia.
Oligozoospermia
Low concentration of spermatozoa in the ejaculate below the lower reference limit. When reporting results, the reference criteria should be specified.
Oocyte
The female gamete (egg).
Oocyte aspiration
Ovarian follicular aspiration performed with the aim of retrieving oocytes.
Oocyte bank
Repository of cryopreserved oocytes stored for future use.
Oocyte cryopreservation
The freezing or vitrification of oocytes for future use.
Oocyte donation
The use of oocytes from an egg donor for reproductive purposes or research.
Oocyte donation cycle
An ART cycle in which oocytes are collected from an egg donor for reproductive purposes or research.
Oocyte maturation triggering
An intervention intended to induce an oocyte in vitro or in vivo to resume meiosis to reach maturity (i.e. to reach metaphase II).
Oocyte recipient cycle
An ART cycle in which a woman receives oocytes from a donor, or her partner if in a same sex relationship, to be used for reproductive purposes.
Oolemma
The cytoplasmic membrane enclosing the oocyte.
Ooplasm
The cytoplasm of the oocyte.