Management of fertility problems including infertility without any specific active clinical or therapeutic interventions other than fertility information and advice, to improve natural fertility, based upon the probability of becoming pregnant.

Birth weight less than 1000 g.

A birth that takes place after 22 but before 28 completed weeks of gestational age.

The probability of a pregnancy, during a single menstrual cycle in a woman with adequate exposure to sperm and no contraception, culminating in a live birth. In population-based studies, fecundability is frequently measured as the monthly probability.

Clinically defined as the capacity to have a live birth.

Infertility caused primarily by female factors encompassing: ovulatory disturbances; diminished ovarian reserve; anatomical, endocrine, genetic, functional or immunological abnormalities of the reproductive system; chronic illness; and sexual conditions incompatible with coitus.

The capacity to establish a clinical pregnancy.

The understanding of reproduction, fecundity, fecundability, and related individual risk factors (e.g. advanced age, sexual health factors such as sexually transmitted infections, and life style factors such as smoking, obesity) and non-individual risk factors (e.g. environmental and work place factors); including the awareness of societal and cultural factors affecting options to meet reproductive family planning, as well as family building needs.

Interventions that include fertility awareness, support and fertility management with an intention to assist individuals and couples to realize their desires associated with reproduction and/or to build a family.

Various interventions, procedures and technologies, including cryopreservation of gametes, embryos or ovarian and testicular tissue to preserve reproductive capacity.

A sequence of biological processes initiated by entry of a spermatozoon into a mature oocyte followed by formation of the pronuclei.

Death of a fetus. It is referred to as early fetal loss when death takes place between 10 and 22 weeks of gestational age; late fetal loss, when death takes place between 22 and 28 weeks of gestational age; and stillbirth when death takes place after 28 weeks gestational age.

The stages of development of an organism from eight completed weeks of fertilization (equivalent to 10 weeks of gestational age) until the end of pregnancy.

An ART cycle in which, after oocyte aspiration, all oocytes and/or embryos are cryopreserved and no oocytes and/or embryos are transferred to a woman in that cycle.

An ART procedure in which cycle monitoring is carried out with the intention of fertilizing thawed/warmed oocytes and performing an embryo transfer.

A birth that takes place between 37 and 42 completed weeks of gestational age.

An ART procedure in which both gametes (oocytes and spermatozoa) are transferred into a Fallopian tube(s).

The nucleus in an oocyte at prophase I.

The age of an embryo or fetus calculated by the best obstetric estimate determined by assessments which may include early ultrasound and the date of the last menstrual period and/or perinatal details. In the case of ART, it is calculated by adding two weeks (14 days) to the number of completed weeks since fertilization. Note: For frozen-thawed embryo transfer (FET) cycles, an estimated date of fertilization is computed by subtracting the combined number of days an embryo was in culture pre-cryopreservation and post-thaw/-warm, from the transfer date of the FET cycle.

A woman who carries a pregnancy with an agreement that she will give the offspring to the intended parent(s). Gametes can originate from the intended parent(s) and/or a third party (or parties). This replaces the term ‘surrogate.’