Endometrial receptivity

1. Benha University Hospital, Egypt
Aboubakr Elnashar

2. 1. Why?
2. What?
3. When?
4. How?
5. Effect of COH on endometrial receptivity
6. Effect of age on endometrial receptivity
7. Assessment of endometrial receptivity:
Functional markers: 1. Biochemical 2. Histological
Clinical assessment: 1.TVS 2. 3DUS 3.Doppler US
8. Improvement of endometrial receptivity
Aboubakr Elnashar

3. The main causes of failure of IVF is
failure embryo implantation.
Embryo implantation depends on:
1.The quality of the embryo
2.Endometrial receptivity.
3. The embryo/endometrial interface
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4. The onset of implantation is a successful
meeting of 2 separate processes: embryo
development & endometrial differentiation.
A synchrony between these functions is
important.
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5. Aboubakr Elnashar

6. Understanding of
1.The mechanisms involved in this
process
2. How to assess? &
3. How to treat its disorders
represent the fundamental steps in the
improvement of IVF.
Aboubakr Elnashar

7. Temporally unique sequence of factors
that make the endometrium receptive to
embryonic implantation
•The window of time when the uterine
environment is conductive to blastocyst
acceptance & subsequent implantation
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8. The endometrium is normally hostile
environment for an embryo , except
during implantation window.
Implantation window:
It is a period during which the
endometrium is optimally receptive to
implanting blastocyst
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9. Duration: 4 to 5 days
D6 to D10 postovulation, or
D7 to D11 post LH surge or
D20 to D24 of 28 D cycle
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10. Benefits of determining the implantation window:
It may be possible to
• Widen the implanation window by
manipulating the pre- & peri-implantation
endocrine environment
• Correlate endocrine, biochemical &
morphological changes with endometrial
receptivity
• Recognize the time for ET that would best
correspond with the implantation window
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11. •Initiation of ER depend on: the down
regulation of endometrial PR & estrogen
receptors induced by P (Lindhard et al,2003).
•When the embryo has arrived in the
endometrial cavity: a preprogrammed
sequence of events occurs, which involves
the secretion of a multitude of biochemical
factors by the endometrium & the embryo,
leading to to the formation of a receptive
endometrium. Aboubakr Elnashar

12. •Some factors like integrins like
 v 3 make the endometrium
receptive & others like MUC1
make it resistant to implantation
except in small areas
Aboubakr Elnashar

13. Abnormalities of the luteal phase
have been detected in all the
stimulation protocols on both
hormonal & endometrial levels.
COH adversely affect endometrial
receptivity(Devroey et al, 2004)Aboubakr Elnashar

14. Etiology:
1. High concentration of estrogens & progesterone,
altered E2 to progesterone ratios.
2. Disturbed LH levels
3. Corpus luteum deficiency (Albano et al, 1998).
4. A direct effect of GnRh agonist or antagonist
on the corpus luteum or on endometrium
5. Altered endometrial receptivity from
endometrial asynchrony & earlier expression
of pinopodes Aboubakr Elnashar

15. •Endometrial histology has revealed a wide
range of abnormalities during the various
ovarian stimulation protocols (Ubaldi et al, 1997).
In GnRh-agonist cycles, mid-luteal biopsies has
revealed:
increased glandulo-stromal dyssynchrony
delay in endometrial development,
strong positivity of endometrial glands for PR,
decreased cell adhesion molecule profiles and
earliest appearance of surface epithelium
pinopodes (Soliman et al, 1994).
Aboubakr Elnashar

16. These factors suggest a shift
forwards of implantation window.
Progesterone supplementation
improves endometrial histology, and
its necessity has been established, at
least in cycles, using GnRh agonists
(Soliman et al, 1994).
Aboubakr Elnashar

17. •There is increased peri-ovulatory P in
the COH cycles. The early rise of P has
a negative impact on endometrial
receptivity but not on oocyte-embryo
quality these cause premature
endometrial lutenization & provide an
explanation for the observed decrease
in endometrial receptivity (De long et al, 2000).
Aboubakr Elnashar

18. On the other hand (Levi et al,2001).
Implantation & pregnancy rates did not
differ between IVF-ET patients and
recipients of donor oocytes.
Exposure of the developing
endometrium to COH during IVF
cycles does not inhibit embryo
implantation or affect pregnancy rate.
Aboubakr Elnashar

19. •Embryo implantation rates declines in a linear
fashion
from 29% in women <34 yr to 5% at 42 yr
(Rosenwaks et al,1995)
Oocyte senescence is responsible but demised
endometrial receptivity may play a role
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20. •Abnormal receptivity in aging subjects
is due to decreased levels of P receptors
promoted by the low levels of E2
receptors (Meldrum,1993).
However when the P dosage for luteal
support was increased, recipients aged
over 40 yr had a marked increase in
pregnancy rate
Aboubakr Elnashar

21. On other hand:
No conclusive evidence of age related histological
changes in the endometrium (Sauer et al,1993).
No difference in implantation, pregnancy,
miscarriage or live-birth rates between younger
& older patients (Abdalla et al,1997)
A study of 3 groups of women ranging from 25
to 60 yr found no difference in histology,
ultrasound, or steroid receptor content of the
endometrium between the different age groups
(Fitzgerald et al,1993)
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22. Aboubakr Elnashar

23. I. Biochemical markers
II. Morphological markers
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24. I. Biochemical markers
1. Endometrial adhesion molecules
Integrins
• 3 integrins are expressed by the endometrium
with a pattern that coincide well with the
window of implantation:
11,
 4 1 &
 v 3 Aboubakr Elnashar

25. Aboubakr Elnashar

26. Aboubakr Elnashar

27. •They are the best markers of endometrial
receptivity
1. They are co-expressed on glandular
epithelium only during cycle D 20 to 24
2. Most interest has been focused on the  v 3
integrin since it appears in endometrial glands &
luminal surface on cycle days 20 to 21,
coincident with the opening of the window of
implantation
3. In endometriosis,  v 3 expression is
reduced
Aboubakr Elnashar

28. Aboubakr Elnashar

29. 4. Integrin expression in the endometrium allows
histologic dating for evaluation of endometrial
receptivity
•Type I defect:
Failure to express  v 3 integrin & out of phase
endometrium. P is effective
Type II defect (Occult endometrial receptivity defect) :
Failure to express  v 3 integrin & in-phase
endometrium.
Mild endometriosis, hydrosalpinx, unexplained
infertility. Aboubakr Elnashar

30. 5. The expression of  4 &  3 on
peripheral blood lymphocytes may
correlate with endometrial cell integrin
expression during peak endometrial
receptive period.
So, it may be used as clinical markers
to assess endometrial receptivity (Reddy et
al,2001).
Aboubakr Elnashar

31. 2. Endometrial anti-adhesion molecules
Mucin 1
3. Endometrial Cytokines
Leukemia inhibitory factor
Interleukin-1
Interleukin-11
Colony-stimulating factor
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32. 4. Endometrial growth factors
Heparin binding-epidermal growth factor
Insulin like growth factor binding protein
5. Other endometrial markers
Mouse ascites Golgi (MAG)
Laminin, fibronectin & collagen IV
Glycodelin
Cyclin E & p27 Aboubakr Elnashar

33. Aboubakr Elnashar

34. Endometrial function tests:
The most efficient way to directly assess endometrial
receptivity (Kliman et al,1995).
1. MAG test:
Endometrial biopsy.
It measures a sticky mucinous substances that is secreted by
endometrial glands before implantation.
85% of normal fertile women express higher levels of MAG
between D 5 & D 18 & no expression after D19.
70% with unexplained infertility showed abnormal MAG
levels.
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35. Delayed pattern: MAG expressed after
D19.
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36. 2. Cyclin E & p27:
It allows dating of the endometrium &
differentiating between normally & abnormally
developing endometrium.
Cyclin E:
First appears in proliferative phase &
not seen after D19
P27:
First appears on D17 & remains for the
rest of the cycle.
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37. Persistent expression of cyclin E
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38. B. Morphological markers
1. Pinopodes
• Globular protrusions in the surface
membrane of endometrial epithelial cells.
• Accurate markers of the implantation
window.
• last for less than 2 days.
Aboubakr Elnashar

39. • The timing of their formation depends on:
1. The hormone treatment applied
2. Patient's individual response.
On average, they form on
days 20-21 in natural,
days 19-20 in COH, and
days 21-22 in HC cycles
Aboubakr Elnashar

40. • There is a wide (up to 5 days) variation
between women in the cycle days on
which pinopodes form.
• Pinopode numbers correlate with implantation
[Nikas et al, 1996]
On other hand: there is evidence of
implantation occurring in the absence of
pinopodes(Redy et al.1997)
Aboubakr Elnashar

41. In natural cycle:
There is an inherent synchrony between the
maturing endometrium & the developing
embryo, ensuring that both will meet at the right
stage.
Fully developed pinopodes have been detected
on days LH+6 to LH+9 (days 19 to 22) in
different individuals
Aboubakr Elnashar

42. SEM of endometrial epithelium on day LH+4 of a natural cycle.
The secretory cells are bulging, covered with dense microvilli.
Ciliated cells are also seen Aboubakr Elnashar

43. Day LH+7 of natural cycle: Most secretory cells bear fully developed
pinopodes, which may protrude beyond the length of the ciliated cellsAboubakr Elnashar

44. Day 21 natural cycle: bulging decreases & small tips of microvilli
reappear on the membrane, which are now wrinkled (Regressing
pinopodes) Aboubakr Elnashar

45. In COH- IVF cycles:
Embryonic development is probably
delayed because of the in vitro conditions
[Lopata,1996] while the endometrium may be
advanced [Nikas et al, 1999] resulting in an early
closure of the implantation window
before the zygote eventually reaches a
stage capable of initiating implantation.
Aboubakr Elnashar

46. Accelerated pinopode formation correlated
strongly with preovulatory progesterone
rise (≥6 ng by day 13)[Develioglu et al, 1999]
Consequently, it would be highly desirable if the
window of receptivity in IVF cycles could be
postponed for a couple of days. A low dose of
mifepristone (antiprogestin) on days 14 and 15
caused delayed pinopode formation [Murphy et al,
1992]
Aboubakr Elnashar

47. A strong correlation between pinopode
number and implantation success after
embryo transfer in a subsequent cycle.
The surface endometrial morphology
during the second cycle was found to be
similar to that in the first cycle
Fully developed pinopodes were detected in
only one sample from each donor, indicating a
short life span.
Aboubakr Elnashar

48. In Hormone –Controlled cycles:
The most receptive day of the cycle corresponds to fully
developed pinopodes or is postulated to be 1 day before
regressing or 1 day after developing pinopodes are observed.
A transfer cycle follows in which synchronization with the
embryo is arranged so that the predicted most receptive day
coincides with embryonic age day 6. It is assumed that by that
time the IVF embryo is ready to implant.
The use of SEM in monitoring endometrial differentiation and
timing of embryo transfer on an individual basis is
recommended.
Aboubakr Elnashar

49. Expression of
pinopodes in
Aboubakr Elnashar

50. Shift of endometrial receptivity & blastocyst in IVF cycles as opposed to
natural cycles Aboubakr Elnashar

51. 2. Decrease in the epithelial tight junctions
between D13 & 23
3. Apoptosis
On D 19-20 apoptosis is detectable in the glands
of the basal layer
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52. Tight junction Apoptosis
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53. Potential functional markers are
expensive,
invasive &
circumstantial Aboubakr Elnashar

54. 1. TVS: Thickness & pattern
Favorable receptivity: Trilaminar pattern (triple line),
Thickness:7-14 mm
Unfavorable receptivity:
Hyperechoic or isoechogenic,
Thickness<7 mm or >14 mm.
>14mm is not associated with reduced
receptivity (Ashkenzai et al,2002)
Aboubakr Elnashar

55. Endometrial thickness:
has a significant positive correlation
with the duration of follicular
stimulation &
an inverse correlation with age.
Endometrial parameters are not reliable
(Mital et al,2002)
Aboubakr Elnashar

56. 2. 3D US:
Endometrial volume:
2 ml is the minimum for a receptive
endometrium
<1ml: no pregnancy (Ragaa et al,1999).
> 4 ml. No increase in ER
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57. Aboubakr Elnashar

58. 3. Doppler US:
Some authors reported significant
correlation between pregnancy
rates & uterine artery Doppler flow
values (Carbillon et al,2001),
while others failed to show such a
relationship (Salle et al,1998)
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59. Aboubakr Elnashar

60. 4. 3D power Doppler US:
Sub-endometrial perfusion can not
predict ER (Kuupesic et al,2001).
Use of subendometrial vascularization
index was superior in predicting the
pregnancy rate of IVF to using
endometrial volume (Ming et al,2003).
Aboubakr Elnashar

61. 5. MRI:
High cost, not used in routine practice
6. laser blood-flowmetry
A novel way to assess ER by measuring
endometrial tissue blood flow, using hystero
fiberscope laser blood-flowmetry.
It is superior to conventional parameters for
determining ER for implantation (Jinno et al,2001).
Aboubakr Elnashar

62. Endometrial receptivity: practical dilemmas
1.There is doubt on the functional
importance of the morphological markers
(Rogers et al,1996)
2. Despite the physiologic importance of the
events cited above, implantation can occur
under a wide range of morphological &
biochemical conditions.
All factors should be investigated
simultaneously, which is impracticalAboubakr Elnashar

63. 1.Tissue sampling, which is often
required for the direct assessment of
markers of endometrial receptivity, is
impossible in actual ET cycles.
It may cause trauma & bleeding at the
implantation site with potential
reduction in the chance of pregnancy.
Aboubakr Elnashar

64. • On the other hand,
Ubaldi et al (1999) found that endometrial aspiration
biopsy at the time of egg collection did not
reduce pregnancy rates in women treated in
IVF-ET.
Recently, Olivennes et al (2003), confirmed that
uterine flushing on the day of egg
retrieval during an IVF-ET cycle did not
adversely affect pregnancy rates.
These results should be confirmed in a larger
sample of a prospective randomized study.
Aboubakr Elnashar

65. I. To develop ovarian stimulation protocols that
cause a minimum reduction in endometrial
receptivity
II. To avoid the endometrium during stimulated
cycles altogether by freezing the embryos &
replacing them in subsequent natural cycles.
III. To improve uterine vascularization.
IV. To treat the pathology:
Aboubakr Elnashar

66. I. To develop ovarian stimulation protocols
that cause a minimum reduction in
endometrial receptivity:
a. Ovarian stimulation protocols that do not use
clomiphene citrate
b. Correcting the endometrial alterations induced by
CC by vaginal supplementation of E2 & P (Elkind et
al, 2002)
c. Return to natural cycle IVF: the disadvantages of
working with a single developing follicle outweigh
any advantages gained (Yaron et al,1997)
Aboubakr Elnashar

67. d. Exogenic 17estradiol during IVF cycles
significantly increases both implantation
rate & pregnancy rates & no difference in
the thickness of the endometrium (Kornilof et
al,1999)
e. Low dose of antiprogesterone may
correct the precocious lutenization &
restore endometrial receptivity (Paulson et al,1997)
Aboubakr Elnashar

68. f. ‘Aromatse inhibitors:
Improving implantation rates in ART by reducing the
supraphysiologic levels of E2 associated with COH
(Mitwally & Casper, 2001; Ziegler et al, 2004)
Endometrial morphology during the implantation
window in letrozole-stimulated cycles was
characterized by in-phase histological dating and
pinopode expression (Cortinez et al, 2005).
{E2 levels similar to spontaneous cycles and higher midluteal
P}
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69. g. Switching the FSH stimulus
to that of LH (or mini HCG) in
the last stages of COH(Ziegler et al, 2004)
Aboubakr Elnashar

70. II. To avoid the endometrium during stimulated
cycles altogether by freezing the embryos &
replacing them in subsequent natural cycles:
Not commonly used
a. Freezing protocols cause a loss in embryo
viability that negate any beneficial effect
b. Practical & financial considerations
Aboubakr Elnashar

71. III. To improve uterine vascularization:
1. Low dose aspirin:
{inhibits the synthesis of thromboxane A2
without affecting the synthesis of
prostacyclin: increase blood flow velocity
in uterine & ovarian artery} (Rubinstein et al,1999).
Aboubakr Elnashar

72. 2. L-arginine (nitric oxide donor):
{NO is formed from arginine by NO synthetase
(Chwalisz et al,2000).
Relaxation of vascular smooth muscles of
endometrial vessels is mediated by NO}.
Oral L-arginine supplementation may
improve uterine blood flow, endometrial
receptivity & implantation rate
Aboubakr Elnashar

73. 3. Sildenafil citrate (viagra):
{is a phosphodiestrase inhibitor that prevents the
break down of cGMP (Cher et al, 2000).
NO relaxes vascular smooth muscles through cGMP}
Dose: 25 mg vaginally 4 times daily with the
beginning of COH until the day of HCG
Larger studies remain necessary to confirm their
effectiveness
Aboubakr Elnashar

74. IV. To treat the pathology:
1. Luteal phase defect: Exogenous
progestrone
2. Fibroids distorting the uterine cavity.
3. IU adhesions
4. Uterine septum
Aboubakr Elnashar

75. 5. Hydrosalpinx:
Negative effect on PR, IR, early pregnancy loss & live
delivery rate per ET.
{The fluid of hydrosalpinx:
constitute a mechanical barrier to implantation by
causing the embryo to float
is deficient to support the developing embryo
toxic to the developing embryo
Inflammatory response
Altered chemical composition of the tubal fluid: low K
& carbonate, proteins }(Lessey et al,1994).
Salpingectomy resulted in improvement of outcomes
(NICE, 2004) Aboubakr Elnashar

76. 6. Endometriosis: Prolonged pituitary
down regulation (Marcus et al,1994).
7. Autoimmune conditions:
prednisolone & low dose aspirin:
increase both implantation &
pregnancy rate (Birkenfield et al,1994)
Aboubakr Elnashar

77. Benha University Hospital, Egypt
Aboubakr Elnashar