The Normal Process of Fertilization

For a couple to conceive a number of processes must take place successfully in both the man and the woman; and, at exactly the right time. The following briefly outlines the steps necessary for conception to take place:

  • During the menstrual cycle, a woman’s hormones regulate the growth, maturation and release of an egg from her ovary. Each month the pituitary gland located in a woman’s brain sends a hormonal signal to her ovaries to prepare an egg for ovulation. These hormones are known as follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
  • The pituitary gland is, in turn, controlled by an area of the woman’s brain known as the hypothalamus, which sends out a hormone known as GnRH, or gonadotropin-releasing hormone. GnRH “tells” the pituitary gland when to release FSH and LH.
  • An increase in FSH stimulates the growth of the developing follicles (and eggs) in the ovary.
  • A large increase in LH signals the ovary to release an egg—this is known as ovulation. Normally, only one of a woman’s two ovaries produces an egg during the woman’s menstrual cycle.
  • The released egg then moves from the ovary into the fallopian tube. The egg remains viable for about 24 hours.
  • For fertilization to occur a sperm must locate and penetrate the awaiting egg while it is in the fallopian tube.
  • If fertilization occurs, the fertilized egg, or embryo, continues to travel down the fallopian tube into the uterus, where it will attach, or implant, into the lining of the uterus.


In order for a couple to conceive, both the male and female reproductive systems must be functioning properly.

In the female this means:

  • Ovulation occurs and leads to the production of a viable egg.
  • The fallopian tubes are open and functioning properly to allow the egg and sperm to meet.
  • The fertilized egg is able to move into the uterus and is not blocked from implanting in the wall of the uterus.
  • The sperm are able to travel through the woman’s vagina, cervix, uterus, and fallopian tubes without being blocked in their attempt to locate the egg.

In the male this means:

  • The testes produce viable, or normal sperm, as well as testosterone, the male hormone.
  • Ability to achieve an erection and engage in sexual intercourse.
  • Normal ejaculation occurs with semen going through the man’s urethra into the vagina.
  • The sperm that are produced are properly shaped, able to move rapidly, and can accurately move to the fallopian tubes to locate and fertilize the egg.

Last modified on: 30 June 2015