"Corpus Luteum" of the Ovary
During the Luteal Phase of the
Ovulation Menstrual Cycle

The corpus luteum is formed from the empty ovarian follicle after it releases an egg at ovulation. It's main role in the reproductive system is to secrete the hormones necessary for conception and pregnancy.


Your egg cells grow inside of ovarian follicles during the follicular phase of your ovulation menstrual cycle. They begin to mature under the influence of follicle stimulating hormone (FSH).

The growing follicles start to secrete an estrogen, known as estradial. When estrogens peak, luteinizing hormone (LH) begins to surge. This increase in LH signals the dominant follicle to release an egg.

After the egg is burst from the ovary, the luteal phase of your ovulation menstrual cycle begins. The empty ovarian follicle then becomes the corpus luteum while still under the influence of luteinizing hormone. It's size can range from 2 to 5 mm.

It continues to produce estrogen and higher levels of progesterone in preparation of a possible pregnancy. This rise, in turn, inhibits FSH and LH.

Your body uses estrogen to further prepare and thicken the endometrial lining of the uterus, the endometrium, for implantation of a fertilized egg. Estrogen is also responsible for the increase in fertile cervical mucus and increased sexual desire that comes just before ovulation.

Progesterone is used by your body to proliferate the endometrium for the purpose of nourishing the implanted fertilized egg by enriching the lining with plenty of blood vessels, among other things. Click here to discover more about natural progesterone cream.

Higher progesterone levels are necessary throughout pregnancy. Though, at about 10 weeks gestation, the placenta takes over production.

If you get pregnant (the egg gets fertilized) then it travels down the fallopian tube into the uterus and burrows itself into the endometrium for implantation. hCG (human chorionic gonadotropin) is then produced by the implanted fertilized egg and its levels will increase.

The rise of HCG (also known as the pregnancy hormone) tells the corpus luteum to continue to produce estrogen and progesterone so as to sustain the pregnancy.

However, if your luteal phase is not long enough (at least 10 days) it doesn't allow enough time for implantation to take place and you may have what is known as luteal phase defect.

If you do not become pregnant (or if pregnancy implantation does not take place), hCG levels do not rise, and within approximately 2 weeks from ovulation, the corpus luteum will begin to degenerate. When this happens, estrogen and progesterone levels will fall.

This drop in hormones in turn signals the endometrial lining to breakdown and be flushed out of the uterus through the vagina. As the hormones necessary for its maintenance are no longer high enough.

Your menstruation period begins and your reproductive cycle starts all over again.

Related pages

Two Week Wait | Pregnancy Implantation | What Happens at Conception? | When Does Conception Occur? | When Does Implantation Occur? | When Does Ovulation Occur? | Human Egg Fertilization | Luteal Phase Defect |

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