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Menstruation & Ovulation

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Presentation on theme: "Menstruation & Ovulation"— Presentation transcript:

1 Menstruation & Ovulation
Dr.Suresh Babu Chaduvula Professor Department of OBGYN College of Medicine

2 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.

3 Menstrual Cycle The 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 menstruation Age of onset – years &average is 13 years

4 (gonadotrophin releasing hormone)
Menstruation is an external indicator of ovarian events controlled by the hypothalamic-pituitary axis Hypothalamus GnRH (gonadotrophin releasing hormone) Pituitary LH FSH + (“gonadotrophins”) Feedback Ovaries Roles of the ovary Gametes (ova) Hormones Steroids (oestradiol, progesterone). Reproductive tract Other targets MENSTRUATION

5 Menstruation ceases between 45-50 years.
Duration – 4-5 days Amount – ml Menstrual discharge consists of blood, mucus, epithelial cells, fragments of endometrium, prostaglandins, enzymes and bacteria.

6 Menstrual cycle is divided into
1] Ovarian 2] Endometrial cycle

7 Timing events in the menstrual cycle. 2. LH surge
OVULATION Days before Days after Day 1 Menstruation Day 1 Follicular phase Luteal phase

8 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

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 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 8th day.

12 Key events in the ovarian cycle
Animated ovarian events Key events in the ovarian cycle OVULATION 1. Follicular growth Day 1 Menstruation Oestradiol

13 Growth of follicles: Oocyte Granulosa cells Thecal cells
Antral follicle Graafian follicle Primordial follicle Oocyte Ovulation Antrum (fluid filled space) Granulosa cells Thecal cells

14 When do follicles start growing?
Many! 30-50 Why is only 1 selected and becomes “dominant”? How many follicles are growing at the start of the cycle? Ovulation When do follicles start growing? In sheep, follicular development takes 180 days 2-3 months earlier! Menstruation

15 What controls follicular growth?
OVULATORY FOLLICLE FSH + LH Ovulation ?????? Gonadotrophin independent In sheep, follicular development takes 180 days Menstruation

In sheep, follicular development takes 180 days OESTRADIOL As 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 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

18 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

19 (non-cellular glycoprotein coat)
The follicle is the fundamental element of the ovary: Blood vessels Granulosa cells Theca Antrum Cumulus cells Oocyte Zona pellucida (non-cellular glycoprotein coat)

20 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

21 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

22 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.

23 3] Stretching factor – Necrobiosis of wall due to passive stretching
4] Contraction of micromuscles in theca externa

24 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.

25 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

26 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 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 luteum 2]17 alfa–OH–progesterone and estradiol 3] Low level of prolactin Life span of Corpus luteum is days.

28 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

29 Luteal- Placental Shift
At weeks corpus luteum function will be taken up by Placenta

30 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

31 Uterine changes in the menstrual cycle.
Endometrial depth More secretion from the glands – hence the term “secretory phase” Oestradiol causes an increase in thickness (the “proliferative phase”) Menstruation OVULATION

32 Optimal time for implantation
Terminal differentiation of stromal cells – “decidualisation” Characteristic “spiral arteries” Optimal time for implantation Menstruation

33 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.

34 Functional Zone stages
1] Stage of regeneration 2] Stage of Proliferation 3] Secretory phase 4] Menstrual phase

35 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 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+P Oestrogen 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 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 ]

39 What causes the onset of menstruation?
Steroid levels fall This is followed by the onset of menstruation

40 How does menstruation stop?
Prolonged vasoconstriction Myometrial contraction Local aggregation of platelets Endothelin and platelet activating factor are potent vasoconstrictors.

41 Regeneration of Endometrium
Oestrogens Growth 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 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

43 Hormones and Ovulation
It occurs after hrs following LH surge. It occurs after hrs following Oestradiol peak of 200 pg/ml Progesterone 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 examined A woman can have periods without ovulation.

45 Abundant mucus - like “raw egg white” of low viscosity mucus increases
Cervical mucus Abundant mucus - like “raw egg white” Production of low viscosity mucus increases Thick, rubbery, high viscosity - impenetrable to sperm. Variable number of “dry” days Menstruation OVULATION

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 temperature Menstruation OVULATION

48 Basal body temperature
Plasma oestradiol Plasma progesterone Volume of cervical mucus – and sperm penetration Uterine 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.

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