Unfertilized Egg: Uterus Lining Changes

When an egg released during ovulation is not fertilized by sperm, a series of hormonal events occurs, leading to changes in the uterus lining (endometrium).

Hormonal Shifts

• After ovulation, if fertilization doesn't happen, the corpus luteum (which produces progesterone) starts to degenerate.
• This leads to a significant drop in progesterone and estrogen levels.

Uterus Lining Response

The thickened, nutrient-rich uterus lining, prepared for a potential pregnancy, is no longer supported by the declining hormone levels.

• The lining begins to break down.
• This breakdown results in the shedding of the inner lining.
• The shedding manifests as menstrual bleeding, consisting of blood and mucous, which is expelled from the body. This process is known as menstruation.

Therefore, if the egg is NOT fertilised, the uterus lining slowly breaks and sheds.