in vivo fertilization

in vivo fertilization

n.

Fertilization of a ripe egg within the uterus of a fertile donor female, rather than in an artificial medium, for subsequent nonsurgical transfer to an infertile recipient.

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in vivo fertilization,

a method of fertilization of an ovum within a fallopian tube of a fertile female donor for transplantation into an infertile recipient.

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fertilization [fer″tĭ-lĭ-za´shun]

in human reproduction, the process by which the male's sperm unites with the female's oocyte, creating a new life. The sex and other biologic traits of the new individual are determined by the combined genes and chromosomes that exist in the sperm and oocyte. See also conception and reproduction. Called also fecundation and impregnation.

After injection into the vagina, millions of sperm cells (spermatozoa) make use of their whiplike tails to swim through the cervix toward the uterus. Most are destroyed along the way by secretions in the vagina, but some reach the uterus and a few may enter the fallopian tubes. A very small number may survive as long as 48 hours. If during this period only one sperm succeeds in entering a fallopian tube and meeting there an oocyte ready to be fertilized, conception can occur. This event is possible only during a period of about 4 days of the month. After the sperm lodges in the oocyte, the tail disappears, but the head unites with the oocyte to form the zygote.

in vitro fertilization the process by which conception takes place in a laboratory medium; the term literally means fertilization “in glass.” A lay term for the product of in vitro fertilization is “test tube baby.”

The treatment cycle involves the following steps: (1) Induction of ovulation with fertility drugs, such as clomiphene citrate, injectable follicle-stimulating hormone/luteinizing hormone, or both, to produce multiple ovarian follicles. When the largest follicle reaches 20 mm in diameter the patient is given an injection of human chorionic gonadotropin to induce expulsion of the oocyte from the follicle. (2) Laparoscopy and follicular aspiration for the harvesting of oocytes. (3) Maturation of retrieved oocytes and inoculation with the husband's or donor's sperm. (4) Incubation of the resulting embryos until they reach the two- to six-cell stage. (5) Transfer of an embryo via catheter into the patient's uterus; at this point intensive intervention ceases, the pregnancy is considered normal, and no further manipulation is required.

in vivo fertilization union of the sperm and ovum within the reproductive tract of the female; usually taken to mean artificial insemination in which the sperm is artificially introduced into the vagina, cervix, or uterine cavity to overcome the problem of infertility.