Female hormones and their role

Female hormones and their role

Have you ever wondered why your body can feel different throughout the month. These changes are driven by hormones. Hormones are chemical messengers that carry signals between the brain and the organs. During the menstrual cycle several hormones work together in a fixed pattern. This ensures that an egg matures, ovulation takes place, and the uterine lining builds up and is shed if pregnancy does not occur.

Your cycle is guided by a small group of hormones that rise and fall to regulate ovulation and menstruation.

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Estrogen

Estrogen plays an important role in the first half of the cycle. This hormone helps rebuild the uterine lining after menstruation. As an egg develops in the ovary, estrogen levels gradually rise. This increase is part of the phase leading up to ovulation.

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Progesterone

Progesterone is mainly active after ovulation, in the second half of the cycle. This hormone helps maintain the uterine lining in preparation for a possible pregnancy. If fertilization does not occur, progesterone levels fall. This drop causes the uterine lining to shed and menstruation begins.

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LH, luteinizing hormone

LH plays a central role around ovulation. A sharp, short rise in this hormone triggers the release of the mature egg from the ovary. Without this LH surge, ovulation does not take place.

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FSH, follicle-stimulating hormone

FSH is especially active at the beginning of the cycle. This hormone stimulates the maturation of a follicle in the ovary that contains an egg. This marks the start of a new cycle.

How these hormones work together

At the start of the cycle FSH stimulates the maturation of an egg. As this happens estrogen rises and the uterine lining rebuilds. Around the middle of the cycle a surge in LH triggers ovulation. After this progesterone supports the second half of the cycle. When progesterone drops, menstruation begins and the cycle starts again.

Sources and references

Cleveland
Clinic, Menstrual Cycle
https://my.clevelandclinic.org/health/articles/10132-menstrual-cycle

NHS,
Fertility in the menstrual cycle
https://www.nhs.uk/conditions/periods/fertility-in-the-menstrual-cycle/

Office on
Women’s Health, Menstrual Cycle
https://www.womenshealth.gov/menstrual-cycle/