Fertilization is the process of union of 2 germ cells, the sperm and the egg, and occurs under normal physiological conditions in the vitelline abdomen of the fallopian tube. Fertilization goes through the processes of sperm capacitation, sperm crossing the oocyte and the radial crown, sperm binding to the zona pellucida of the egg, sperm undergoing the acrosome reaction and crossing the zona pellucida, sperm fusing with the egg, egg activation, and the formation of the male and female progenitors. When the fertilized egg, the starting point of new life, is formed, the fertilized egg moves toward the uterus while beginning to cleave, eventually reaching a place in the uterine wall and implanting in the endometrium, i.e., implantation. After a total of about 270 days of gestation, a new life is born. Chao Lan, Fertility Treatment Center, Qilu Hospital of Shandong University
Factors affecting sperm-egg union.
After ovulation, the egg remains fertile for only 6-24 hours; the sperm enters the female reproductive tract and generally remains fertile for only 1-2 days; the amount of semen ejaculated by the male should be 2-4 ml each time, while the number of sperm in each ml should be 20-100 million.
Prerequisites for fertilization.
For the female.
Ø Ovaries can ovulate normally.
Ø The umbilical part of the fallopian tube can pick up eggs normally.
Ø At least one open and functioning fallopian tube.
Ø normal functioning eggs.
Ø normal endometrial tolerance.
Male partner.
Ø adequate number of forward moving sperm.
Ø sperm that can penetrate the cervical mucus
Ø spermatozoa that can reach the abdomen of the fallopian tube.
Ø normal sperm capacitation and fertilization ability.
In modern medicine, two years of marriage (one year in some countries), normal sexual intercourse without contraception and no pregnancy, or two years of cohabitation without pregnancy, are called infertility or sterility.
Assisted Reproductive Technology (ART): A technology that uses medical means to help infertility patients become pregnant, also known as assisted conception technology, ART mainly includes artificial insemination and in vitro fertilization-embryo transfer and its derivative technologies.