Presentation on theme: "Menstruation & Ovulation Dr.Suresh Babu Chaduvula Professor Department of OBGYN College of Medicine."— Presentation transcript:
Menstruation & Ovulation Dr.Suresh Babu Chaduvula Professor Department of OBGYN College of Medicine
Menstruation Definition: The visible manifestation of cyclic physiologic uterine bleeding due to shedding of the endometrium. Due to invisible interplay of hormones through hypo-thalamo-pituitary-ovarian axis. For menstruation to occur axis should be active, endometrium should be receptive and outflow tract should be patent.
Menstrual Cycle The period extending from first day of period until the 1 st day of next period. Normal length of a cycle is between 28-32 days. Mean – 28 days. It occurs cyclically between 21-35 days. Menarche: First menstruation Age of onset – 11-15 years &average is 13 years
Ovaries Reproductive tract Other targets Steroids Feedback Hypothalamus GnRH (gonadotrophin releasing hormone) Pituitary LH FSH + (“gonadotrophins”) Menstruation is an external indicator of ovarian events controlled by the hypothalamic- pituitary axis Roles of the ovary 1.Gametes (ova) 2.Hormones MENSTRUATION (oestradiol, progesterone).
Menstruation ceases between 45-50 years. Duration – 4-5 days Amount – 20-80 ml Menstrual discharge consists of blood, mucus, epithelial cells, fragments of endometrium, prostaglandins, enzymes and bacteria.
Menstrual cycle is divided into 1] Ovarian 2] Endometrial cycle
Timing events in the menstrual cycle. 2. LH surge Day 1 Menstruation Day 1 OVULATION Days beforeDays after Follicular phaseLuteal phase
Ovarian Cycle Development and maturation of a follicle, ovulation and formation of corpus luteum and its degeneration All these events occur in 4 weeks 1] Recruitment of group of follicles 2] Selection and maturation of dominant follicle 3] Ovulation 4] Corpus luteum formation and degeneration
Recruitment of Follicles Out of many primordial follicles only 20 antral follicles are developed in each cycle. All these follicles from 2-5 mm size are influenced by FSH. Those follicles not influenced by FSH will become atretic. Oocyte of each follicle grow out of proportion.Oocyte is surrounded by acellular glycoprotein from follicular cells called Zona pellucida
Flattened outer pregranulosa cells will become Granulosa cells. These cells contain FSH receptors.
Selection of a Dominant follicle and maturation Dominant follicle is called as Graafian Follicle out of 30-50 follicles from many primordial follicle. Starts from 5-7 days Follicle with high oestrogen and with maximum FSH receptors in granulosa cells will become a dominant one. Rest of follicles will become atretic by 8 th day.
Day 1 Menstruation OVULATION Animated ovarian events Oestradiol 1. Follicular growth Key events in the ovarian cycle
Menstruation Ovulation OVULATORY FOLLICLE As each follicle grows, it produces increasing amounts of oestradiol. FSH + LH OESTRADIOL
Cumulus oophorus or Discus proligerous anchors the ovum to to the wall of follicle Corona radiata – radially arranged cells around the ovum At this stage FSH induces LH receptors in granulosa cells of dominant follicle LH receptor induction is essential for mid cycle LH surge for ovulation and lutenisation of granulosa cells to form corpus luteum and secretion of progesterone
Graafian Follicle Graafian follicle measures 20 mm before ovulation It has following layers from outside inward 1] Theca externa 2] Theca interna 3] Membrana granulosa 4] granulosa cell layer 5] discus proligerous 6] corona radiata woth ovum inside And 7] antrum with fluid
Theca Granulosa cells Cumulus cells Blood vessels Antrum Oocyte Zona pellucida (non-cellular glycoprotein coat) The follicle is the fundamental element of the ovary:
Graafian Follicle and its Fluid Fluid contains: 1]Oestrogens 2] FSH 3] traces of androgens 4] Prolactin 5] OMI-oocyte maturation inhibitor 6] LI – lutenisation inhibitor 7] Inhibin 8] Proteolytic enzymes 9] Plasmin
Time for development of a Follicle Total duration - 3 months Upto antral stage of 1mm – 2months Upto 5 mm stage – 2 weeks Upto 20 mm – 2 weeks
Ovulation Causes: 1] LH surge – secondary to sustained peak level of estrogens in the late follicular phase. This will cause completion of reduction division in the oocyte and lutenisation of granulosa cells, synthesise progesterone andprostaglandins. 2] FSH rise- leads to plasminogen and it helps in lysis of follicle.
3] Stretching factor – Necrobiosis of wall due to passive stretching 4] Contraction of micromuscles in theca externa
Effects of Ovulation Following ovulation the follicle is changed to corpus luteum. Ovum will be picked up by fallopian tube and may fertilise or degenerate.
Corpus Luteum Life cycle is divided into 4 stages: 1] stage of proliferation 2] stage of vascularisation 3] stage of maturation and 4] stage of regression
Stage of Proliferation: Granulosa cells will become polyhedral and enlarged and with lipids –looks greyish yellow called granulosa lutein cells Stage of vascularisation: small capillaries grow towards granulosa layer. Stage of maturation: After 1 week reaches 1-2cm and a carotene pigment will give a yellow color Stage of regression: on 22 -23 day regression starts.Lutein cells become atrophic and will become white called Corpus Albicans / if pregnancy occurs it will become Corpus luteum of pregnancy.
Hormones for formation and maintenance of corpus luteum 1] FSH induces LH receptors and LH surge causes lutenisation of granulosa cells and progesterone secretion.LH scretion should be continuous for function of corpus luteum 2]17 alfa–OH–progesterone and estradiol 3] Low level of prolactin Life span of Corpus luteum is 12-14 days.
Hormones from Corpus luteum 1] Progesterone 2] Oestrogen 3] Inhibin 4] Relaxin In absence of pregnancy levels of O+P+I decreases leading to rise in FSH and this in turn leads to recruitment of new follicles
Luteal- Placental Shift At 7- 10 weeks corpus luteum function will be taken up by Placenta
Endometrial or Uterine Cycle Endometrium contains surface epithelium, glands, stroma and blood vessels Endometrium has 2 zones: 1] Basal [ stratum basalis ] 2] Superficial functional zone
Uterine changes in the menstrual cycle. Menstruation OVULATION Oestradiol causes an increase in thickness (the “proliferative phase”) More secretion from the glands – hence the term “secretory phase” Endometrial depth
Menstruation Characteristic “spiral arteries” Terminal differentiation of stromal cells – “decidualisation” Optimal time for implantation
Stratum Basalis:[ 1mm ] Ocupies 1/3 of endometrium – basal arteries+ Not influenced by hormones Regeneration occurs from it. Functional zone: Responds to hormones like O+P In an ovulatory cycle four stages are seen.
Functional Zone stages 1] Stage of regeneration 2] Stage of Proliferation 3] Secretory phase 4] Menstrual phase
Stage of regeneration: Starts before menstruation and completes after 2-3 days after periods. Measures 2mm. Glands are lined by cubical cells Stage of Proliferation: Extends from 5-6th day to 14 th day due to Estrogens.Glands are tubular and perpendicular to surface. Epithelium is columnar with nuclei at base, stromal cells are spindle shaped with spiral vessels upto epithelium. Subepithelial congestion +. Measures 3-4 mm.
Secretory Phase: Effects of O+P Oestrogen induces Progesterone receptors and progesterone is responsible for secretory phase. Starts at 15 th day to 5-6 days prior to menstruation. Epithelium is more columnar and ciliated. Glands increase in size with taller epithelium with vacuoles formation- subnuclear vacuolation.
First and earliest effect of progesterone is appearence of subnucleolar vacuolation.It will persist upto 21 days. Saw toothed glandular epithelium, glands become corkscrew shaped with marked spiralling of vessels. Measures 6-8 mm. Regresssion of endometrium starts 24-48 hrs prior to periods. Marked spiralling of vessels and withdrawl of hormones causes tissue hypoxia and anoxia.
Menstrual phase Degeneration and casting off endometrium due to regression of corpus luteum with fall in level of O+P. Degeneration is due to stasis of blood and spasm of vessels leading to damage of vessels with escape of blood. Proteolytic enzymes from lysosomes causes local damage.[ Enzymatic autodigestion ]
What causes the onset of menstruation? Steroid levels fall This is followed by the onset of menstruation
How does menstruation stop? Prolonged vasoconstriction Myometrial contraction Local aggregation of platelets Endothelin and platelet activating factor are potent vasoconstrictors.
Regeneration of Endometrium Oestrogens Growth factors
Hormones of ovarian and endometrial cycle At menstruation Oestrogen and inhibin are at low levels and high FSH. Oestrogen increases gradually and FSH decreases and remains static at day 5. O+ LH and androgen increases. Matuaration of follicle is combined effect of FSH and LH/ Peptides –Inhibin, Activin and Follistatin Growth Facors – IGF, EGF from theca cells – modulate FSH,LH and peptide actions. IGF stimulates aromatase activity and progesterone synthesis. Progesterone will increase in secretory phase until 5 days before periods. LH will start declining
Hormones and Ovulation It occurs after 10-12 hrs following LH surge. It occurs after 24-36 hrs following Oestradiol peak of 200 pg/ml Progesterone peaks at 8 th day after LH surge.
Datting of endometrium – Examination of endometrium Luteal phase defect – A discrepancy of more than 2 days in the postovulatory phase when endometrium is examined A woman can have periods without ovulation.
Cervical mucus Menstruation OVULATION Variable number of “dry” days Production of low viscosity mucus increases Abundant mucus - like “raw egg white” Thick, rubbery, high viscosity - impenetrable to sperm.
With increasing oestradiol: 1. The mucus becomes more abundant - up to 30x more and its water content increases. 2. Its pH becomes alkaline. 3. Increased elasticity – ("spinnbarkeit test") 5. “Ferning pattern” caused by the interaction of high concentrations of salt and water with the glycoproteins in the mucus. Characteristic fernlike pattern as the mucus dries on a glass slide.
Menstruation OVULATION A small (0.5 o C) rise in BBT typically follows ovulation. Basal body temperature
Plasma oestradiol Plasma progesterone Volume of cervical mucus – and sperm penetration Uterine endometrium
a) Calendar Method - which is essentially based on the previous menstrual history. b) Temperature method - using a midcycle rise in body temperature as a sign when ovulation has occurred. c) Cervical changes - which can be detected by feeling the cervix and cervical mucus. d) Hormonal methods - using over-the-counter "kits" to assess urinary hormone levels. There are a number of potential ways of trying to identify the “fertile” period..: