Corpus Luteum

The corpus luteum is a temporary endocrine structure that forms in the ovary after ovulation. Its main role is to produce progesterone, a hormone essential for maintaining a potential pregnancy in the early stages.

🧬 How the corpus luteum forms:

  1. During the first half of the menstrual cycle, follicle-stimulating hormone (FSH) causes ovarian follicles to mature.
  2. One follicle becomes dominant and releases an egg during ovulation (triggered by the luteinizing hormone (LH) surge).
  3. After the egg is released, the remains of the follicle transform into the corpus luteum.

🩸 What the corpus luteum does:

FunctionHormonal Role
Produces progesteroneMaintains the uterine lining (endometrium) so a fertilized egg can implant and grow
Produces estrogenWorks with progesterone to stabilize the endometrium
Supports early pregnancyIf pregnancy occurs, hCG (from the embryo) keeps the corpus luteum active until the placenta takes over

❌ What happens if pregnancy does not occur:

  • The corpus luteum has a lifespan of about 10–14 days.
  • If no pregnancy occurs, it breaks down into a small mass of scar tissue called the corpus albicans.
  • This leads to a drop in progesterone, which triggers menstruation.

✅ Summary Table

TermDefinition
Corpus luteumTemporary hormone-producing gland formed after ovulation
Main hormoneProgesterone, plus some estrogen
Lifespan~10–14 days without pregnancy; sustained if hCG is present
ImportancePrepares and maintains the uterine lining for implantation