MENSTRUAL CYCLE REGULATION

Misbah Akram

Menstruation??? Natural changes that occur in the uterus

and ovary as an essential part of making sexual reproduction possible.

Essential for the production of eggs, and for the preparation of the uterus for pregnancy.

Average length= 28 days

Ages of 11 and 14

Controlled by hormones

Interaction between hypothalamus, pituitary, ovaries & uterus.

Each cycle divided into phases

Each female reproductive cycle has two components:

Ovarian cycle Uterine cycle

Ovarian CycleOvulation occurs at 14th day of 28-days

ovarian cycle.14 days prior to ovulation are called

follicular phase.While 14 days after ovulation constitute

luteal phase.

Uterine Cycle Ovulation occurs at 14th day of 28-days uterine

cycle. 14 days prior to ovulation are subdivided into

menstrual phase (day 1-5) and a proliferative phase (6 -14) .

While 14 days after ovulation constitute secretory phase.

In the first 5 days, GnRH stimulates anterior pituitary to increase production of FSH and LH.

Day 1-5: Primordial follicle matures to primary follicles each containing a diploid primary oocyte.

Day 6-13: Primary follicles form secondary follicles.

After 16 hours: FSH & LH Maturation of follicle called graafian follicle.

Just prior to ovulation, primary oocyte complets meiosis 1 to form secondary haploid oocyte.

Follicular Phase

Ovulation• Release of

secondary oocyte from mature follicle.

• Guided by high level of LH.

Luteal Phase•Days: 15-28•Remaining ovarian follicular cells form a yellowish structure called corpus luteum.•Production of progesterone and estrogen by corpus luteum

Menstrual Phase

• Progesterone Shedding of endometrial lining.

• Woman’s period.

Proliferative Phase

• Estrogen produced by follicular cells endometrian begins to reform

Secretory Phase• Days: 15-28• Progesterone and estrogen from

corpus luteum stimulates further thickening of the endometrium.

In case of no fertilization:• Corpus luteum becomes corpus

albicans.• Decreased level of progesterone and

estrogen • Leads to menstruation.

Gonadotrophin

releasing

hormones

Follicle stimulati

ng hormon

es

Leuteinizing

hormones

estrogen progesteron

HORMONES ARE

*Gonadotropin-releasing hormone

Five hormones involved in an elaborate scheme involving both positive and negative feedback

Cyclic secretion of GnRH* from the hypothalamusAnd of FSH and LH from the anterior pituitary orchestrates the female reproductive cycle

ROLE of GnRH IN THE MENSTRUAL CYCLE

• The hypothalamus secretes GnRH in a pulsatile fashion

• GnRH activity is first evident at puberty

• Follicular phase GnRH pulses occur hourly

• Luteal phase GnRH pulses occur every 90 minutes

• Loss of pulsatility down regulation of pituitary receptors secretion of gonadotropins

• Release of GnRH is modulated by –ve feedback by: steroids gonadotropins

• Release of GnRH is modulated by external neural signals

1. High levels of estrogens suppress the release of GnRH (bar) providing a

negative-feedback control of hormone levels.

2.  Secretion of GnRH depends on certain neurons in the hypothalamus

which express a gene (KISS-1) encoding a protein of 145 amino acids.

From this are cut several short peptides collectively called kisspeptin.

These are secreted and bind to G-protein-coupled receptors on the

surface of the GnRH neurons stimulating them to release GnRH.

However, high levels of estrogen inhibit the secretion of kisspeptin and

suppress further production of those hormones.

Follicle Stimulating Hormone

(FSH)

Site of Secretion Pituitary gland

Target Organ Ovary

Function stimulates the

growth & development of

the follicle stimulates

secretion of oestrogen

effect of LH in stimulating ovulation

Oestrogen

Ovary

Endometrium (lining of the uterus) stimulates

repair of uterine lining at high conc. inhibits FSH,

however during 'pituitary

hormone surge' it stimulates further FSH production

as conc. peaks stimulates

release of LH

Lutenising Hormone (LH)

Pituitary

Ovary stimulates the

final development of

the follicle stimulates ovulation

stimulates the development of

the corpus luteum

stimulates production of progesterone

Progestrone

Corpus luteum

Uterus maintains uterine lining endometrium) inhibits release

of FSH inhibits release

of LH fall in conc. results in

menstruation fall in conc.

removes inhibition of

FSH and a new cycle begins.

Found in follicular fluidStimulates FSH induced estrogen production gonadotropin receptorsandrogenNo real stimulation of FSH secretion in vivo (bound to protein in serum)

Local peptide in the follicular fluid-ve feed back on pituitary FSH secreationLocally enhances LH-induced androstenedione production

ACTIVINS

INHIBINS

Hormonal feedback control of menstrual cycle

Hormones of Placenta The placenta forms large quantities of human chorionic

gonadotropin, estrogen, progesterone and human chorionic somatomammotropin, which are all essential to a normal pregnancy

HUMAN CHORIONIC GONADOTROPIN (HCG) HCG is a glycoprotein with a molecular weight of 39,000.

It is secreted by the syncytial trophoblast cells and can be measured in the blood 8 to 9 days after ovulation.

The rate of secretion rises rapidly to reach maximum bout 10 to 12 weeks after ovulation and decreases to much lower value by 16 to 20 weeks after ovulation.

It continues at this level for the remainder of pregnancy.

• This hormone is identical to LH in its effect and therefore is able to maintain the corpus luteum past the time when it would otherwise regress.

• The secretion of estradiol and progesterone is thus maintained and menstruation is normally prevented.

• Diagnosis of the early pregnancy

MENSTRUAL DISEASES

DYSMENORRHEA (PAINFUL CRAMPS)

MENORRHAGIA

AMENORRHEA/OLIGOMENORRHEA

PREMENSTRUAL SYNDROME

UTERINE FIBROIDS

ENDOMETRIOSIS

POLYCYSTIC OVARIAN SYNDROME 

DYSFUNCTIONAL UTERINE BLEEDING (DUB)

OTHER RISK FACTORS INCLUDE:

Weight. Smoking and Alcohol Use. Stress. Menstrual Cycles and Flow. Chronic Pelvic Pain Diet Too much exercise

POSSIBLE COMPLICATIONS anemia osteoporosis infertility quality of life

DIAGNOSIS

first the patient history blood and hormonal tests ultrasound

OTHER DIAGNOSTIC PROCEDURES

Hysteroscopy Laparoscopy Endometrial Biopsy Dilation and Curettage (D&C)

MEDICATIONS

Nonsteroidal Anti-inflammatory Drugs (NSAIDs) levonorgestrol, drospirenone, norgestrol, norethindrone, and

desogestrel. PROGESTINS Gonadotropin releasing hormone (GnRH) agonists