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Biology LibreTexts

43.7D: Infertility

  • Page ID
    14138
  • LEARNING OBJECTIVES

    • Define infertility and discuss ways in which it can be treated

    Infertility is the inability to conceive or carry a fetus to birth. About 75% of causes of infertility can be identified. These include diseases (such as sexually-transmitted diseases that can cause scarring of the reproductive tubes in either men or women) or developmental problems frequently related to abnormal hormone levels in one of the individuals. Inadequate nutrition, especially starvation, can delay menstruation. Stress can also lead to infertility. Short-term stress can affect hormone levels, while long-term stress can delay puberty, causing less-frequent menstrual cycles. Other factors that affect fertility include toxins (such as cadmium), tobacco smoking, marijuana use, gonadal injuries, and aging.

    If the cause of infertility is identified, several assisted reproductive technologies (ART) are available to aid conception. A common type of assisted reproductive technology is in vitro fertilization (IVF) where an egg and sperm are combined outside the body and then placed in the uterus. Eggs are obtained from the woman after extensive hormonal treatments that prepare mature eggs for fertilization and prepare the uterus for implantation of the fertilized egg. Sperm are obtained from the male and combined with the eggs, which are then supported through several cell divisions to ensure viability of the zygotes. When the embryos have reached the eight-cell stage, one or more is implanted into the woman’s uterus. If fertilization is not accomplished by simple IVF, a procedure known as intracytoplasmic sperm injection (ICSI) can be used to inject the sperm into an egg. IVF procedures produce a surplus of fertilized eggs and embryos that can be frozen and stored for future use; the procedures can also result in multiple births.

    image
    Figure \(\PageIndex{1}\): Intracytoplasmic sperm injection: A sperm is inserted into an egg for fertilization during intracytoplasmic sperm injection (ICSI).

    Key Points

    • Infertility can have many causes, such as sexually transmitted diseases, toxins, malnutrition, drug use, stress, and age.
    • Infertility can be treated by assisted reproductive technologies in which science intervenes, attempting to aid conception through artificial means.
    • In vitro fertilization is a type of assisted reproductive technology in which an egg is fertilized by a sperm outside the body, grows to the eight- cell stage, and is then implanted in the uterus.

    Key Terms

    • infertility: the inability to conceive children
    • assisted reproductive technology: the technological means of inducing pregnancy (by means of artificial insemination or other techniques)

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