Learning Objectibves : 1.To define and describe the mechanism of ovulation 2.To review the different phases of the menstrual cycle and its physiology " Ovulation (ovum release) occurs when estradiol levels usually peak as the ovulatory phase begins. Progesterone levels also begin to increase. Stored LH is released in massive amounts (LH surge), usually over 36 to 48 hours, with a smaller increase in FSH.

1. Dr Aditya Das
Fertility Consultant & Trainer
Keya FERTILITY & Embryoedu
Bhubaneswar, India
Member , Neoindia Fertility Society (NIFS)
Member , ISAR , ESHRE,ISMAAR

2. Good Evening & Welcome

3. Ovulation Induction & IUI Webinar
Module 1 & 2 / 16.05.2020/8pm IST
Reprod. Endocrinology of
Ovulation
Dr Aditya Das , Keya Fertility
& Embryoedu
Founding Member , NIFS &
WHF , INDIA

5. Learning Objectives
To define and describe the mechanism of ovulation
To review the different phases of the menstrual cycle and its
physiology

6. HPO axis
•Firstly the hypothalamic hormones
(GnRH)
•Secondly, the pituitary hormones
(FSH and LH)
•Finally, the ovarian steroid hormones
(estradiol and progesterone)

8. HPO Axis

9. MENSTRUAL CYCLE

10. Follicular phase
- begins when estrogen levels are low
- recruitment
- selection of dominant follicle
- increasing levels of estradiol and inhibin B
Ovulatory phase
- LH surge
- Rupture of preovulatory follicle
- release of a viable oocyte

11. Luteal phase
• Now empty follicle changes to a yellow colour, becomes
corpus luteum
• Continues to secrete estrogen, but now beings to release
progesterone
• Progesterone further develops uterine lining
• If pregnant, embryo will release hormones to preserve corpus
luteum

16. RELATIVE HORMONAL CHANGES

18. Follicular Phase :Growing Follicle
The growing follicle passes through the distinct stages that are
defined by certain structural characteristics:

19. Growing Follicle

20. Growing Follicle
1.Oocyte increasing in size
2.Multilayered granulosa cells become cuboidal
3.Aromatisation androgen to estrogen induced by FSH
4.Increase FSH receptors , induced by FSH and E2
5. Theca cell layer forms surrounding stroma

22. What is Recruitment
(i) initial transition of primordial follicles from the resting pool
into the pre-antral growth phase,
(ii) the cyclic recruitment of a cohort of antral follicles (2–5 mm)
during the menstrual cycle following puberty

23. What is Selection
two different phenomena:
(i) the recruitment of a cohort of 2–5-mm antral follicles and
(ii) the preferential growth of a species-specific number of large
antral follicles from the recruited cohort.
The follicle that is selected from the recruited cohort has been
referred to as the ‘dominant’ follicle, while all other follicles of
the cohort which undergo atresia have been ‘subdominant’

24. Recruitment & Selection
Follicle ‘recruitment’ refers to the emergence of a group or
cohort of medium-size (2–5 mm) antral follicles.
‘Selection’ refers to the preferential growth of the dominant
follicle from the cohort of recruited antral follicles.

25. Follicle Divergence
At the time of selection, the growth profile of the dominant
follicle begins to ‘diverge’ as it continues to grow while the
subordinate follicles undergo atresia.
Divergence occurs when the dominant follicle reaches a
diameter of ∼10 mm on Day 6–9 of the follicular phase in
women

26. Follicle Divergence

28. 2 Cell 2 Gonadotropin Hypothesis
1. In early stage :
theca cells : LH receptors only
granulosa cells : FSH Receptor only
LH  theca cells  Androgens
Aromatisation
Granulosa Cells : Androgens ----- Estrogen
FSH

29. 2 Cell 2 Gonadotropin Hypothesis

31. ‘FSH Threshold/Window/Gate Concept’ (Brown,
1978; Baird, 1987; Schipper et al., 1998)

33. ‘FSH Threshold/Window/Gate Concept’
(Brown, 1978; Baird, 1987; Schipper et al., 1998)

34. Follicle Dominance
Growth of dominant follicle is due to
1. Greater contents of FSH Receptors
2. Enhancement of FSH action due to high intrafollicular FSH
level

35. Follicle Dominance
1. Dominant follicle suppresses the growth of subordinates
through an inhibitory effect on circulating FSH concentrations
2 .Subordinate follicles not able to thrive in declining FSH and
therefore succumb to atresia

36. LH Ceiling Hypothesis
• Each follicle has an upper limit of responsiveness to LH beyond
which follicle maturation ceases and degeneration occurs.
• Thus, the dominant follicle would have a much higher ceiling than
the non-dominant ones, leading to their regression at the time of
the LH surge.
• Low-dose stimulation with low-dose LH : enhances
steroidogenesis without inhibiting cell proliferation
• High dose LH : suppresses granulosa proliferation, atresia of
immature follicles and premature luteinization of preovulatory
follicles.

37. LH Surge
• Dominant follicle continues to secrete estrogen.
• The persistent high level of estrogen
(greater than 200 pg/ml for approx 50 hrs
induces an abrupt release of LH from the pituitary gland
• Negative feedback turns into positive feedback
• this hormonal surge then triggers ovulation.

39. LH Surge
• LH surge precedes ovulation by 35–44 hr
• peak sLH precedes ovulation by 10–12

41. • acidic FSH isoforms provoke the formation of inhibin-B and
inhibin-A in the granulosa cells of follicles with a diameter of
3–13 mm with high efficacy.
• inhibin-B peak occurs in the circulation around the mid-
follicular phase.

42. Inhibin–A & Inhibin–B in Folliculogenesis

43. • Inhibin-B shows a peak in the circulation around cycle day 7,
simultaneous with selection of the dominant follicle
• estradiol and inhibin-A only start to increase a few days later
suggesting that inhibin-B is mainly responsible for
downregulating pituitary FSH release.
• Inhinin B : an important physiological hormone in follicular
selection

44. AMH in Ovulation
• expressed by granulosa cells of the ovary
• limits the formation of primary follicles by inhibiting excessive
follicular recruitment by FSH.
• reduces aromatase activity and sensitivity of follicles to FSH
stimulation.
• elevated serum AMH may indicate a higher threshold for
response to ovulation induction in women PCOS.
• - J Clin Endocrinol Metab. 2016 Sep; 101(9): 3288–3296.

46. • in PCOS, baseline serum AMH levels were higher among women
who did not respond to ovulation induction,
• absolute level of AMH could not be found above which women did
not respond
• AMH levels were significantly lower among women who ovulated.
• women with higher baseline AMH levels required higher doses of
clomiphene or letrozole to achieve ovulation.
• AMH may be a marker of ovarian resistance to ovulation induction.

47. USG : Signs of Ovulation

48. USG : Signs of Ovulation
• Disappearance or sudden decrease in follicle size.
• Increased echogenicity inside the follicle, indicating corpus luteum
formation.
• Free fluid in pelvis (or pouch of Douglas).
• Replacement of “triple‐line appearance” of endometrium by
homogenous, hyperechoic “luteinized” endometrium.

49. Ovulation Trigger
• End point of any ovulation induction protocol is to indentify
the best time for triggering ovulation.
• Most crucial step
• Critical timing for HCG administation depends on the criteria for follicular
maturity
1. Follicular diameter
2. Serum E2 (500-1500pg/ml)
3. Endometrial thickness (9-10mm)
• Always time HCG with follicle size
Gnt follicles mature at 15-18 mm
CC follicles mature at 18-20 mm (Sperof,f 2005)

50. HCG as Ovulation Trigger
• Substitute for LH surge
• Control the timing of ovulation
• Timing of SI. / IUI / OR
• HCG has a half-life of about 35 h: support the initial part of the
luteal phase.

51. HCG as Ovulation Trigger
• Cochrane Database of Systematic Reviews
• “ Evidence is inadequate to recommend or refute the use of u
hCG as an ovulation trigger in anovulatory women treated with
CC ”

52. IUI Timing
• around the moment of ovulation.
• 24 0r 36 H after HCG : IUI 36 h after hCG has marginally better
pregnancy rates than 24 h.
• Timing of insemination may be kept at 24 or 36 h after hCG
injection to suit the convenience of the clinic or care provider.
(Rahman et al, 2011)
• Since different time intervals between hCG and IUI did not
result in different pregnancy rates, a more flexible approach
might be allowed.

53. Luteal Phase Endocrinology
- CL formed from the pre-ovulatory follicle under the action of
the mid-cycle LH surge.
- LH controls luteal structure and function alongwith
progesterone .

54. - If conception does not take place, luteolysis occurs as a
physiological apoptotic process.
- HCG , secreted after implantation rescues the corpus luteum
and extend its lifespan.

55. - In OI cycles, the negative feedback effect of the ovarian
steroids on the pituitary is markedly potentiated, leading to
the suppression of endogenous LH secretion during the whole
menstrual cycle.
- Marked suppression of LH secretion disrupts CL function
regardless of the treatment regimen.

56. Luteal Follicular Transition Phase
• 2days prior to menstruation
• Demise of CL leads to decrease in negative feedback by luteal
steroids and inhibin A
• Incresae in GnRH pulse frequency
• Increase rise in FSH

57. STUDIES REVEAL
• 1/3 rd of infertility is due to male partners
• 1/3 rd of infertility is due to female partners.
• Remaining part is unknown and called as idiopathic infertility.

58. RATIONALE : OI in IUI
“ Disorders of ovulation or Anovulatory patients
comprise of 30-40% of all female factor infertility “
“ May present with oligomenorrhoea / amenorrhea “

59. WHO Classification
• Group I : Hypothalamic Pituitary Failure
(Hypogonadotropic Hypogonadism)
• Group II :Hypothalamic Pituitary Dysfunction
( Normogonadotropic , PCOS)
• Group III : Ovarian Failure
(Hypergonadotropic Hypogonadism)

60. RATIONALE : OI in IUI
• Normogonadotrophic anovulation
most common category of anovulatory infertility
• Within this group, polycystic ovary syndrome (PCOS) is by far the most
prevalent cause

61. Ovarian Stimulation Or Induction
• Ovulatory Patients : Contolled Ovarian Stimulation or Superovulation
• Anovulatory Patients : Ovarian Induction

62. Ovarian Stimulation Or Induction
• Superovulation is useful in
• Transient anovulation
• Mild or moderate oligoasthenospermia
• Cervical factor
• Mild endometriosis
• Unexplained infertility

63. Take Home Messages / Module 1
• Aim: to restore normal fertility to anovulatory women
• Generate normo-ovulatory cycles
• Mimic physiology and induce a single or more than one dominant
follicle
• Avoid multiple pregnancy and OHSS
• Within a tight therapeutic margin

64. Thank You

65. Wait for few seconds …..Wait for few seconds …..
SESSION : Two