insemination

Insemination is the introduction of semen into the female reproductive tract to achieve fertilization. In humans and other animals, it can occur naturally or through artificial means. Natural insemination typically occurs during sexual intercourse, when semen is deposited in the vagina and sperm travel through the cervix and uterus to reach an ovum.

Artificial insemination (AI) refers to procedures that place semen into the female reproductive tract by nonsexual means. Common methods include intracervical insemination (ICI), where semen is placed at the cervix; intrauterine insemination (IUI), where semen is deposited directly into the uterus; and, less commonly, intratubal insemination (ITI), with injection into the fallopian tubes. In humans, semen may be fresh or cryopreserved and is often processed to concentrate motile sperm.

Timing is important and is coordinated with ovulation, using monitoring, ultrasound, or hormones to maximize the chance of fertilization. AI is used for fertility treatment, donor insemination, single-parent families, or when natural insemination is not possible or desired. In animals, AI is widely used in breeding programs and dairy or meat production, enabling genetic selection and disease control.

Outcomes vary by method, age, and fertility factors. In humans, success rates per cycle for IUI are generally in the low to mid teens for many couples, decreasing with age; multiple pregnancy risk increases with certain protocols. Risks include infection, discomfort, and, with fertility drugs, higher chance of twins or more.

Ethical and regulatory considerations include donor screening and consent, privacy, and veterinary or agricultural regulations for animal AI.