The embryo transfer technique is the final and most crucial step of the IVF cycle. It requires close collaboration between the clinician and embryologist. While around 80% of embryos typically reach the transfer stage, the pregnancy rate remains low due to factors such as poor embryo quality and technique. The success of embryo transfer depends on proper preparation, including evaluating the cervico-uterine axis, clearing mucus from the cervix, and using ultrasound guidance. The embryo must be placed in the optimal location of the uterine cavity to maximize implantation chances. Attention to factors such as catheter type, duration of embryo loading, and prevention of uterine contractions can significantly improve clinical pregnancy outcomes.

1. Aisha M. Elbareg, MD, PhD
Associate Clinical Professor & Senior Consultant
IVF Unit, Al-Amal Hospital, Misurata, Libya

2. The entire IVF cycle depends on a delicate placement of the
embryos at the proper location near the middle of the
endometrial cavity where implantation is maximized with
minimal trauma and manipulation.
Embryo Transfer

3. Embryo Transfer
 Final and most crucial step in IVF cycle in which embryos are
placed in the uterus, and necessitates close collaboration
between clinician and embryologist.
 App. 80% reach ET, but low pregnancy rate. Without healthy
embryos, embryo transfer will fail.
 Poor embryo transfer technique often results in embryo
implantation failure .
 Significant improvement in clinical pregnancy rates can be
achieved by giving due attention to ET technique.

4. • Select the best seed
• Prepare the soil
• Plant at the appropriate time with
proper technique

5. Factors affecting embryo implantation
 Implantation capacity of the embryo
 Endometrial receptivity
 Embryo transfer technique

6. Preimplantation embryo development

7. The embryo
 Failure of embryo to implant is the major limiting step in
determining ART success rate.
 A number of strategies aimed at increasing chances of
embryo to successfully implant:
Blastocyst culture - PGD
Assisted hatching
Co-culture with human endomet -epithelial cells
Embryo Glue

8. GlueEmbryo
•
special medium for the embryo transfer which eases the embryo's
adhesion to the mucous membrane of the uterus via the use of
biochemical signals. The consistency of embryo glue is similar to
that of the liquid of the mucous membrane of the uterus and
contains an important substance which help the media to wrap
itself around the embryo and assists in bonding of the embryo to
the mucous membrane via its ‘sticky' properties.

9. The endometrium
 Human endometrium is a dynamic tissue.
 In the phase of receptivity, the endometrium
undergoes morphological, cytoskeletal,
biochemical, and genetic changes.
 The period of E. receptivity is known as WOI.
 WOI opens on day 19 or 20 of the cycle, remains
for just 4-5 days when the P4 reaches peak.

10. Assessment of E. Receptivity
 USS measurement of end.:
Thickness, pattern, volume,
doppler of uterine and
subendometrial blood flow in
prediction of successful
implantation
 Histological assessment of
endometrial biopsy.
 Gene expression profiling.
(ERA)

11. Assessment of E. Receptivity
 triple lines of 7-14mm thickness indicates favorable
receptivity.
 Histology is performed on tissue section where only a small
area of the surface can be examined.
 Scanning electron microscopy is most appropriate to study
Pinopodes formation.
 The developments in microarray technology now allow
more reliable, quantifiable gene expression monitoring.
These tech. have been used to investigate the
transcriptomics of human endometrium in the different
phases of menstrual cycle, including the receptive phase.

12. Technique of ET

13. 1. Disruption of endometrium
2. Induction of uterine contractions
3. Deposition of embryos in a suboptimal location
4. Damage of embryos during the process
What may go wrong during transfer ?

14. What is difficult Transfer ?
 Prolonged time to negotiate uterocervical angle
 Tenaculum application
 Blood in or on the catheter
 Stiff embryo transfer catheter

15. Why is it difficult to transfer ?
 Cervical stenosis
 Acute angle of uterocervical portion
 (anteversion/retroversion)
 Unexperienced operator

16. Laboratory Part
1. Embryo Selection (Grade, Stage, no. and timing)
2. Handling of catheter
3. Embryo loaded method of embryo in catheter
4. Embryo Loading medium
5. Duration of embryo loading
6. Check presence of blood or mucus in/out catheter
Variables Influencing the Success of
Embryo Transfer Technique

17. Clinician Part
1. The preparation before embryo transfer
2. Uterine Contractions
3. Way of Catheter Insertion
4. Placement of the Catheter Tip
5. Types of catheter!!
Variables Influencing the Success of
Embryo Transfer Technique

18. 3 stages of preparation
First stage: the preparation before ET
1. Evaluating the cervico-uterine axis by:
 USS
 A dummy (Mock transfer) (Madani et al., 2009)
2. Appropriate evaluation of uterine cavity.
 USS, Hysteroscopy
 Many unexpected agents make entering the uterine cavity
difficult, such as cervical polyps or fibroids, a pin-point external
os, and cervical deformation due to congenital anomalies or
previous surgery, all of which can be discovered by a ‘dummy’ or
‘mock’ transfer. In the case of cervical stenosis, cervical
dilatation should be performed before ovarian stimulation.

19. Second stage: measures during ET
1. Cervical preparation, removing of
mucous or blood
2. Straightening of the utero-cervical angle
3. Use of US guidance
4. Types of catheter: Wallace, Labotect,
Cook and Frydman. Benefits of one over the
Other are controversial!!
5. Loading the embryo medium/embryo Glue
6. Embryo load method for transfer
3 stages of preparation

20. Presence of blood or mucous in/out catheter
The presence of blood on the outside of the
catheter tip :
1. May be a sign of difficult embryo transfer
2. Associated with lower pregnancy rates
3. A higher incidence of retained embryos

21. Mucus plugging of the catheter tip
1. Can cause embryo retention and damage
2. Improper embryo placement
3. Affect the rate of embryo expulsion into the cervix.
4. A source of contamination of the endometrial
cavity and the embryos.
Presence of blood or mucous in/out catheter

22. Preparation of cervix: Removal of mucus

25. 6. Embryo load method for transfer
• Embryos could expel into vagina, if transfer
medium exceeds 60 μl.
• Implantation could be affected when medium
was less than 10 μl .

26. 7. Time of ET with regard to uterine contraction
problem:
 Serum P at the time of ET
 Difficult ET with use of tenaculum
 Progesterone into the luteal phase- blastocyst
transfer.
8. Injection of air before ET catheter withdrawal with
Slow withdrawal of transfer catheter.

27. Third stage: measures after ET
Prevention of the expulsion of fluids & embryo
from cx
Closing the cx
Fibrin sealant
Bed rest!!!!!!!!!!!!
βhCG test 14 days after ET.
Adequate luteal support+ low dose Aspirin&
or LMWH wherever indicated.

28. Consider
Single embryo transfer (blastocyst)
Later frozen embryo transfer

29. Blastocyst ET
 Blastocyst culture
 Blastocyst development
 Compaction, cavitation
 Blastocyst scoring & grading system
 Blastocyst selection for transfer

30. Way of catheter insertion

31. Favorable prognosis for Elective
Single ET
 Expectation of one or more high-quality embryos
available for cryopreservation
 Eupolid embryos
 Previous live birth after an IVF cycle
 The availability of vitrified, high-quality, day-5, or
day-6 blastocysts for transfer

32. embryo transfer cycles-In frozen
 Favorable characteristics should be based on The age
of the woman when the embryos were frozen
 presence of high quality vitrified embryos.
 1st FET cycle
 previous live birth after an IVF cycle.
 Embryo transfer numbers should not exceed the
recommended limit on the number of fresh embryos
transferred for each age group.

33. factors associated with ET success12
1. Removal of hydrosalpnix.
2. Ultrasound details of uterine cavity.
3. Dummy (Mock) transfer before treatment.
4. Ultrasound-guided transfer.
5. Removal of the cervical mucus plug.
6. Avoiding the use of a tenaculum.
7. Types of catheter used.
8. Absence of bleeding.

34. 9. Not touching the fundus.
10. Keeping catheter stationary for at least 1 min.
11. 30 minutes rest after transfer.
12. Giving antiprostaglandins to prevent contraction.
factors associated with ET success12

35. ASRM guidelines
 Review prior mock or transfer patient notes for the
level of difficulty and tips for guiding the procedure.
 Prepare patient : need for analgesia (Grad C).
 Acupuncture (Grade B).
 Identification and matching of patient and embryos
 Use USS GUIDE (Grad A).
 Clinician preparation: hands wash, latex-free gloves
(Grade B).

36.  Speculum, flush and cleanse cx/vagina with cotton
swab or gauze sponge using media or NS.
 Remove mucus from endocervical canal (Grade B).
 Using soft catheter (Grad A).
 Placement of the catheter tip in the upper or
middle of uterine cavity > 1 cm from fundus (Grade
B).
ASRM guidelines