Menstrual cycle

Notice how each graph relates to the others

The menstrual cycle is a process that uninseminated human women go through about every 28 days. During this time, the women's ovaries create a mature ovum (egg). Then the woman's body prepares for pregnancy by thickening the walls of the uterus. If the woman does not become pregnant during this time, the egg and the lining of the uterus come out of the woman's body during menstruation.[1]

The menstrual cycle process is controlled by four major hormones: FSH (follicle stimulating hormone); LH (luteinising hormone); estrogen; and progesterone. These hormones prepare the uterus to receive a fertilized egg and control its development.[2]

The menstrual cycle has three stages: the Follicular stage, Ovulation, and the Luteal (or premenstrual) stage. The cycle will stop if the woman gets pregnant (if a fertilized egg implants itself into the lining of the uterus).[2]

Follicular Stage

This stage is the start of the menstrual cycle, and is counted as day one of the cycle. This stage starts when the amount of progesterone and estrogen in a woman's blood drop. This causes the endometrium - the thick lining of the uterus - to leave the woman's body through menstruation. It will appear as bleeding from the vagina. This stage lasts from 4–6 days.[3]

At the start of this stage, the pituitary gland will begin to release more FSH. This will continue for 3-4 days. The FSH makes several follicles grow in one of the ovaries. Each follicle contains an immature ova (egg). These follicles create estrogen.[3]

Usually, the amount of FSH in the body peaks during the third or fourth day of menstruation. All but one of the follicles dies off. The one that is left releases even more estrogen. Once again, the lining of the uterus thickens. Near the end of the stage, a woman's estrogen levels peak. This causes the pituitary gland to release LH, which also peaks at this time.[2]

Other Languages
Alemannisch: Menstruationszyklus
العربية: دورة شهرية
azərbaycanca: Heyz
français: Cycle menstruel
한국어: 월경 주기
हिन्दी: मासिक धर्म
italiano: Ciclo mestruale
ಕನ್ನಡ: ಋತುಚಕ್ರ
Kreyòl ayisyen: Sik menstriyèl
Bahasa Melayu: Kitaran haid
Nederlands: Menstruatiecyclus
português: Ciclo menstrual
română: Ciclu menstrual
Runa Simi: K'ikuy
slovenščina: Menstruacijski ciklus
srpskohrvatski / српскохрватски: Menstrualni ciklus
Basa Sunda: Siklus ménstruasi
татарча/tatarça: Менструаль цикл
తెలుగు: ఋతుచక్రం
Tiếng Việt: Chu kỳ kinh nguyệt
中文: 月經週期