Presentation on theme: "Menstruation & Ovulation"— Presentation transcript:
1 Menstruation & Ovulation Dr.Suresh Babu ChaduvulaProfessorDepartment of OBGYNCollege of Medicine
2 MenstruationDefinition: 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.
3 Menstrual CycleThe period extending from first day of period until the 1st day of next period.Normal length of a cycle is between days. Mean – 28 days.It occurs cyclically between days.Menarche: First menstruationAge of onset – years &average is 13 years
4 (gonadotrophin releasing hormone) Menstruation is an external indicator of ovarian events controlled by the hypothalamic-pituitary axisHypothalamusGnRH(gonadotrophin releasing hormone)PituitaryLHFSH+(“gonadotrophins”)FeedbackOvariesRoles of the ovaryGametes (ova)HormonesSteroids(oestradiol,progesterone).Reproductive tractOther targetsMENSTRUATION
5 Menstruation ceases between 45-50 years. Duration – 4-5 daysAmount – mlMenstrual discharge consists of blood, mucus,epithelial cells, fragments of endometrium, prostaglandins, enzymes and bacteria.
6 Menstrual cycle is divided into 1] Ovarian2] Endometrial cycle
7 Timing events in the menstrual cycle. 2. LH surge OVULATIONDays beforeDays afterDay 1MenstruationDay 1Follicular phaseLuteal phase
8 Ovarian CycleDevelopment and maturation of a follicle, ovulation and formation of corpus luteum and its degenerationAll these events occur in 4 weeks1] Recruitment of group of follicles2] Selection and maturation of dominant follicle3] Ovulation4] Corpus luteum formation and degeneration
9 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
10 Flattened outer pregranulosa cells will become Granulosa cells Flattened outer pregranulosa cells will become Granulosa cells. These cells contain FSH receptors.
11 Selection of a Dominant follicle and maturation Dominant follicle is called as Graafian Follicle out of follicles from many primordial follicle.Starts from 5-7 daysFollicle with high oestrogen and with maximum FSH receptors in granulosa cells will become a dominant one.Rest of follicles will become atretic by 8th day.
12 Key events in the ovarian cycle Animated ovarian eventsKey events in the ovarian cycleOVULATION1. Follicular growthDay 1MenstruationOestradiol
14 When do follicles start growing? Many! 30-50Why is only 1 selected and becomes “dominant”?How many follicles are growing at the start of the cycle?OvulationWhen do follicles start growing?In sheep, follicular development takes 180 days2-3 months earlier!Menstruation
15 What controls follicular growth? OVULATORY FOLLICLEFSH+ LHOvulation??????Gonadotrophin independentIn sheep, follicular development takes 180 daysMenstruation
16 FSH Menstruation OVULATORY FOLLICLE + LH Ovulation OESTRADIOL In sheep, follicular development takes 180 daysOESTRADIOLAs each follicle grows, it produces increasing amounts of oestradiol.Menstruation
17 Cumulus oophorus or Discus proligerous anchors the ovum to to the wall of follicle Corona radiata – radially arranged cells around the ovumAt this stage FSH induces LH receptors in granulosa cells of dominant follicleLH receptor induction is essential for mid cycle LH surge for ovulation and lutenisation of granulosa cells to form corpus luteum and secretion of progesterone
18 Graafian Follicle Graafian follicle measures 20 mm before ovulation It has following layers from outside inward1] Theca externa2] Theca interna3] Membrana granulosa4] granulosa cell layer5] discus proligerous6] corona radiata woth ovum insideAnd 7] antrum with fluid
19 (non-cellular glycoprotein coat) The follicle is the fundamental element of the ovary:Blood vesselsGranulosa cellsThecaAntrumCumuluscellsOocyteZona pellucida(non-cellular glycoprotein coat)
20 Graafian Follicle and its Fluid Fluid contains:1]Oestrogens2] FSH3] traces of androgens4] Prolactin5] OMI-oocyte maturation inhibitor6] LI – lutenisation inhibitor7] Inhibin8] Proteolytic enzymes9] Plasmin
21 Time for development of a Follicle Total duration - 3 monthsUpto antral stage of 1mm – 2monthsUpto 5 mm stage – 2 weeksUpto 20 mm – 2 weeks
22 OvulationCauses: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.
23 3] Stretching factor – Necrobiosis of wall due to passive stretching 4] Contraction of micromuscles in theca externa
24 Effects of OvulationFollowing ovulation the follicle is changed to corpus luteum.Ovum will be picked up by fallopian tube and may fertilise or degenerate.
25 Corpus Luteum Life cycle is divided into 4 stages: 1] stage of proliferation2] stage of vascularisation3] stage of maturation and4] stage of regression
26 Stage of Proliferation: Granulosa cells will become polyhedral and enlarged and with lipids –looks greyish yellow called granulosa lutein cellsStage 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 colorStage of regression: on day regression starts.Lutein cells become atrophic and will become white called Corpus Albicans / if pregnancy occurs it will become Corpus luteum of pregnancy.
27 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 luteum2]17 alfa–OH–progesterone and estradiol3] Low level of prolactinLife span of Corpus luteum is days.
28 Hormones from Corpus luteum 1] Progesterone2] Oestrogen3] Inhibin4] RelaxinIn absence of pregnancy levels of O+P+I decreases leading to rise in FSH and this in turn leads to recruitment of new follicles
29 Luteal- Placental Shift At weeks corpus luteum function will be taken up by Placenta
30 Endometrial or Uterine Cycle Endometrium containssurface epithelium,glands,stroma andblood vesselsEndometrium has 2 zones:1] Basal [ stratum basalis ]2] Superficial functional zone
31 Uterine changes in the menstrual cycle. Endometrial depthMore secretion from the glands – hence the term “secretory phase”Oestradiol causes an increase in thickness (the “proliferative phase”)MenstruationOVULATION
32 Optimal time for implantation Terminal differentiation of stromal cells – “decidualisation”Characteristic “spiral arteries”Optimal time for implantationMenstruation
33 Stratum Basalis:[ 1mm ]Ocupies 1/3 of endometrium – basal arteries+Not influenced by hormonesRegeneration occurs from it.Functional zone:Responds to hormones like O+PIn an ovulatory cycle four stages are seen.
34 Functional Zone stages 1] Stage of regeneration2] Stage of Proliferation3] Secretory phase4] Menstrual phase
35 Stage of regeneration: Starts before menstruation and completes after 2-3 days after periods. Measures 2mm.Glands are lined by cubical cellsStage of Proliferation:Extends from 5-6th day to 14th 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.
36 Secretory Phase:Effects of O+POestrogen induces Progesterone receptors and progesterone is responsible for secretory phase.Starts at 15th 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.
37 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 hrs prior to periods.Marked spiralling of vessels and withdrawl of hormones causes tissue hypoxia and anoxia.
38 Menstrual phaseDegeneration 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 ]
39 What causes the onset of menstruation? Steroid levels fallThis is followed by the onset of menstruation
40 How does menstruation stop? Prolonged vasoconstrictionMyometrial contractionLocal aggregation of plateletsEndothelin and platelet activating factor are potent vasoconstrictors.
41 Regeneration of Endometrium OestrogensGrowth factors
42 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 FollistatinGrowth 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
43 Hormones and Ovulation It occurs after hrs following LH surge.It occurs after hrs following Oestradiol peak of 200 pg/mlProgesterone peaks at 8th day after LH surge.
44 Datting of endometrium – Examination of endometrium Luteal phase defect – A discrepancy of more than 2 days in the postovulatory phase when endometrium is examinedA woman can have periods without ovulation.
45 Abundant mucus - like “raw egg white” of low viscosity mucus increases Cervical mucusAbundant mucus - like “raw egg white”Productionof low viscosity mucus increasesThick, rubbery, high viscosity - impenetrable to sperm.Variable number of “dry” daysMenstruationOVULATION
46 Characteristic fernlike pattern as the mucus dries on a glass slide. 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.
47 A small (0.5 oC) rise in BBT typically follows ovulation. Basal body temperatureMenstruationOVULATION
48 Basal body temperature Plasma oestradiolPlasma progesteroneVolume of cervical mucus – and sperm penetrationUterine endometrium
49 There are a number of potential ways of trying to identify the “fertile” period..: 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.