Unfertilized Egg: Female Reproductive Process

When a female human's ovulated egg is not fertilized by sperm, the body initiates a process to shed the uterine lining that was prepared for potential pregnancy.

Menstruation Explained

The key events are:

• The egg travels through the fallopian tube. If no sperm are present for fertilization within approximately 12-24 hours, the egg begins to degenerate.
• Simultaneously, the levels of hormones like progesterone and estrogen decrease significantly because pregnancy has not occurred.
• This hormonal drop causes the thickened uterine lining (endometrium) to break down and shed.
• The shedding of the uterine lining, accompanied by bleeding, is called menstruation. This typically occurs about 14 days after ovulation if fertilization does not happen.

Why Other Options Are Incorrect

• Formation of zygote: This process requires the fusion of sperm and egg (fertilization), which did not occur.
• Childbirth: This is the end result of a full-term pregnancy, which begins with fertilization.
• Embryo development: This stage follows fertilization and implantation of the embryo in the uterus.

Therefore, when the egg is not fertilized, menstruation is the process that occurs.