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.