C

Cancelled/abandoned cycle: Cancelled cycles are those where drugs were administered or the patient was prepared for treatment but where egg collection did not take place.
   


Capacitation: A process that occurs to sperm, which gives them the ability to penetrate and fertilise an egg, as they pass through the female genital tract. This can also be mimicked in a culture medium.

Cell: The basic unit of all living organisms.  Complex organisms such as humans are composed of somatic (body) cells and germ line (reproductive) cells. 

Cervical mucus: The secretions surrounding the cervical canal.  The amount and texture changes during ovulation to allow sperm penetration. 

Cervix: The narrow passage at the lower end of the uterus (womb), which connects to the vagina.

Chlamydia: A sexually transmitted disease which can cause damage to the female and male reproductive systems resulting in infertility. Chlamydia may remain undetected for long periods of time.

Chorion: The outer membrane tissue of the primitive placenta. 

Chorion villus sampling (CVS): A procedure, usually between 8 and 12 weeks of pregnancy, by which a small amount of the chorionic villi from the placenta is biopsied for genetic analysis. 

Chromosome: A threadlike structure of DNA and associated proteins which is found in the nucleus of a cell. Chromosomes carry genetic information in the form of genes.


Cleavage: The process which occurs to the zygote (cell formed by fertilisation) to result in a blastocyst.

Clomid:  A drug used in stimulated DI and IUI cycles.

Clomiphene: A fertility drug which stimulates the production of one or more follicles and therefore increases the chances of pregnancy. 

Cloning: The production of two or more genetically identical individuals by nucleus substitution or by mechanical division of a cleaving zygote to yield identical cells each of which can form a new individual. Also known as Cell Nuclear Replacement (CNR).

Congenital malformations: Any malformation which is noticed at birth, whether the result of  a genetic (inherited) or environmental cause.

Counselling: Aims to enable patients to understand the implications of infertility treatment, to give emotional support and to help the patient cope with the consequences of treatment. 

Corpus luteum: A yellow structure which develops within the ruptured ovarian follicle after the egg has been released. The corpus luteum secretes progesterone.

Cryopreservation: The storage of gametes or embryos by freezing at low temperatures.

Cyclogest: A drug which can be taken rectally or vaginally and supports the hormone levels of patients undergoing fertility treatment following insemination.

Cytomegalovirus (CMV):  A member of the herpes groups of viruses. Most adults and children who catch CMV have no symptoms, although some people may get a fever, sore throat, fatigue and swollen glands. CMV is of most risk to unborn children of women who get CMV for the first time during pregnancy. About 7 to 10% of these babies will have symptoms at birth or will develop disabilities including mental retardation, small head size, hearing loss, and delays in development.