Roles of Oestrogen & Progesterone in the Menstrual Cycle

Oestrogen

Female sex hormone that controls secondary sexual characteristics and rebuilds uterus lining

Progesterone

Hormone that maintains the uterus lining and supports pregnancy

Menstrual cycle

Monthly cycle preparing the uterus for pregnancy

Ovulation

Release of an egg from the ovary

FSH

Hormone that stimulates egg development

LH

Hormone that triggers ovulation

Uterus lining

Tissue that thickens to support embryo implantation

What does oestrogen do?

Rebuilds and thickens the uterus lining after menstruation

What else does oestrogen do?

Stimulates LH release and inhibits FSH

Why does oestrogen inhibit FSH?

To prevent multiple eggs maturing at once

What triggers ovulation?

A surge in LH

What does progesterone do?

Maintains the thick uterus lining

Where is progesterone produced?

By the ovary after ovulation (corpus luteum)

What happens to progesterone if no fertilisation occurs?

Levels fall

What does a fall in progesterone cause?

The uterus lining breaks down (menstruation)

What happens to progesterone if pregnancy occurs?

Levels stay high to maintain the lining

Why must progesterone stay high in pregnancy?

To prevent the uterus lining from shedding

Which hormone stimulates LH release?

Oestrogen

Which hormone prevents ovulation during pregnancy?

Progesterone

Which hormone thickens the uterus lining?

Oestrogen

Which hormone maintains the uterus lining?

Progesterone