Normal Menstruation Aboubakr Elnashar

Benha university Hospital, Egypt

ABOUBAKR ELNASHAR

The process

Complex

aspects of its initiation, control, and cessation:

not fully understood.

The average ages: menarche: 12.8 y

menopause: 51 y

Day 1 of a cycle:

first day of fresh bleeding and this should always

be clarified on history of LMP.

ABOUBAKR ELNASHAR

Follicular phase

Pulsatile release of

hypothalamic GnRH: anterior

pituitary to produce FSH.

FSH promotes ovarian

follicular development:

recruitment of a dominant follicle

containing oocyte.

Follicular granulosa cells

produce oestrogen: endometrial

proliferation.

Inc oestrogen levels: -ve

feedback on the hypothalamo-

pituitary (HP) axis (via follicular

inhibin) to stop further FSH

production. ABOUBAKR ELNASHAR

Ovulation

Increasing dominant follicle oestrogen (positive

feedback via follicular activin): altered

hypothalamic GnRH pulsatility: pituitary production

of LH: LH surge 36h before ovulation.

ABOUBAKR ELNASHAR

Luteal phase

The follicle collapses down to become the corpus

luteum (CL) ('yellow body'), which produces

oestrogen and progesterone (from theca cells).

Progesterone and oestrogen act on an

oestrogen-primed endometrium to induce

secretory changes: thickening and inc vascularity.

The corpus luteum has a fixed lifespan of 14 days

(programmed cell death) before undergoing

involution: corpus albicans ('white body').

ABOUBAKR ELNASHAR

ABOUBAKR ELNASHAR

ABOUBAKR ELNASHAR

If implantation occurs:

hCG (luteotrophic) 'rescue' of the CL allows

continued production of progesterone to support

the endometrium.

In the absence of pregnancy:

CL degeneration: a rapid fall in progesterone and

oestrogen, initiating menstruation.

ABOUBAKR ELNASHAR

Menstrual phase

Rapid dec in steroids: shedding of the unused

endometrium.

Inflammatory mediators (PGs, ILs, and tumour

necrosis factor (TNF): vasospasm (approx. 24h) in

spiral end arteries: hypoxia and endometrial

devitalization.

Vasodilatation and spiral artery collapse: loss of

the layer and bleeding from vessels

Endometrium lost down to basalis layer (1/3 of

loss reabsorbed).

ABOUBAKR ELNASHAR

Complex vascular changes controlled by above

secondary messengers, also: natural haemostatic

mechanisms including platelet plugs, coagulation

cascade, and fibrinolysis.

All steroid hormones now at basal level, negative

feedback is lifted, and GnRH-FSH production can

begin a new cycle.

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Normal cycle or pathological?

Ovulatory cycles

•Regular

•usually 21-32 days

{variable follicular phase} (luteal phase fixed).

•Shorter or longer cycles usually result from oligo-

ovulationl/ anovulation.

After menarche:

• Cycles often irregular for months or for several

years

• {immaturation of the HPO axis}

ABOUBAKR ELNASHAR

Peri-menopausal periods

•Commonly irregular (usually inc cycle length)

•{ovarian resistance to gonadotrophins and

anovulatory cycles}.

>45yrs

•irregular, chaotic, or constant bleeding:

•investigation to exclude genital tract cancer.

ABOUBAKR ELNASHAR

Bleeding

Duration

1-7days with an average of 3-5 days.

Amount

•highly variable.

•Periods described as 'heavy' should always be

viewed as such.

Abnormal

•lMB

•PCB

•totally erratic/constant bleeding

ABOUBAKR ELNASHAR

Pain

Normal

{vasospasm and ischaemia}

highly variable.

Abnormal: interfering with normal functioning

needs

ABOUBAKR ELNASHAR

ABOUBAKR ELNASHAR