Overview of Normal Conception

In order to conceive and give birth to a baby, a particularly ordered process must occur:

  • Egg development stimulating hormones must be made in the brain and pituitary and be released properly.
  • The egg must be of sufficient quality and be chromosomally normal.
  • The egg must develop to maturity.
  • The brain must release a sufficient surge of the Luteinizing Hormone to stimulate final maturation of the egg.
  • The follicle where the egg develops in the ovary must rupture and release the egg.
  • The fallopian tube must “pick up’ the egg.
  • The sperm must survive their brief visit in the vagina, enter the cervical mucous, swim to the fallopian tube and reach the egg.
  • The sperm must be able to get through the cumulus cells around the egg and bind to the shell (zona pellucida) of the egg.
  • The sperm must undergo a biochemical reaction and release their DNA package (23 chromosomes) into the egg.
  • The fertilized egg must begin to divide.
  • The early embryo must continue to divide and develop normally.
  • After three days, the embryo should have traveled down into the uterus from the fallopian tube.
  • The embryo must continue to develop and expand into a blastocyst (the cluster of cells from which the embryo arises).
  • The outer layer of cells develops the placenta and other supporting tissues needed for fetal development.
  • The blastocyst must hatch out of its shell.
  • The endometrial lining of the uterus must be properly developed and receive the blastocyst, where it must attach and implant.
  • Many complex embryonic and fetal development follow.