EMBRYO TRANSFER

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EMBRYO TRANSFER

• Dr. M. Hakan ÖZÖRNEK
• EUROFERTIL
• Reproductive Health Center
• Istanbul, Turkey

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Variables affecting pregnancy rates

• Uterine receptivity
• Embryo quality
• Transfer efficiency

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• ET is the final and most crucial step in IVF
• ET technique has been given little attention and
  the published data on the subject are minimal.
• But it is not as simple as it looks

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Variables affecting ET success

• Trial transfer
• Cervical mucus
• Catheter typ
• Difficult ET
• Ultrasound quidance

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Embryo transfer
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• Significant differences were observed in
  pregnancy rates after the embryo transfer was
  performed by different clinicians
• Hearn-Stokes, et al., Fertil Steril, 2000

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Trial transfer

• A trial transfer in a cycle preceding IVF for the
  purpose of measuring the uterine cavity depth and
  direction apperars to be of value.

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Trial transfer

• 335 patients
• Pregnancy rates
• Trial group 22.8
• No trial group 13.1
• Mansour, et al., Hum Reprod, 1994

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Trial transfer

• Because of the great variability in cervical and
  uterine anatomy a trial transfer is beneficial.

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Cervical mucus

• Mucus plugging of the catheter tip can cause
• Retained embryos
• Damage to the embryos
• Improper embryo placement

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Cervical mucus

• Cervical lavage before ET to remove all visible
  mucus
• 55 pregnancy rate with lavage
• 41 pregnancy rate without lavage
• Mac Namee

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Cervical mucus

• Embryos may be retained in the catheter owing to
  plugging of the tip with mucus or uterine tissue.
• Visser (1993) found a decrease in pregnancy rates
  from 20 to 3 when embryos were retained.

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Cervical mucus

• Cervical mucus can plug the tip of the catheter
• The embryos can stick to the cervical mucus
  around the catheter and be dragged outside during
  the withdrawal of the catheter.

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Cervical mucus

• In a retrospective study analysing 1204 embryo
  transfer procedures, it was shown that the
  embryos were much more likely to be retained when
  the embryo transfer catheter was contaminated
  with mucus or blood.
• Nabi, et al., Hum Reprod, 1997

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Catheters

• The ideal embryo transfer catheter should be soft
  enough to avoid any trauma to the endocervix or
  endometrium and malleable enough to find its way
  into the uterine cavity

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Catheter type

• Although stiff catheters and use of a rigid outer
  sheath make catheter placement easier, they may
  result in more bleeding, trauma, mucus plugging
  and stimulation of uterine contractions.

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Catheter type

• Soft catheters allow the tip to follow the
  contour of the cervical and uterine axis and
  minimize trauma to the endometrium.

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Catheter type

• Pregnancy rate with different catheters
• Frydman 32
• Wallace 19
• TDT 19
• Wisanto, et al., Fertil Steril, 1989

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Catheter type

• Pregnancy rate with different catheters
• Frydman 31
• Wallace 30
• Al-shawaf, et al., J Assist Reprod Genet,
  1993
• 518 IVF cycles
• Soft catheter 36
• Hard catheter 17
• Wood, et al., Hum Reprod, 2000

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Catheter type

• Pregnancy rate with different catheters
• Tomcat 35
• Wallace 63
• M-Wallace 69
• Schoolcraft, et al., 2003

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Catheter type

• A large volume (60µl) of transfer media and a
  large air interface have been shown to result in
  embryos which were expelled
• into the cervix
• on the speculum or
• adherent to the catheter
• Removing the air column minimized such
  complication

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Avoiding any uterine contractility

• Use soft catheters
• Avoid touching the uterine fundus
• Try to gentle manipulation

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Uterine contractility

• It was demonstrated that only 45 of embryos were
  present within the uterine cavity 1 h after the
  transfer.
• Menezo, et al., Acta Europ Fertil, 1985
• Stimulation of the cervix causes the release of
  oxytocin, thus increasing uterine contractility.

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Touching the uterine fundus

• It is a fact that if the tip of the catheter
  touches the uterine fundus the patients
  experience immediate discomfort followed by
  suprapubic pain
• Touching the fundus with the catheter stimulated
  junctional zone contactions that can reduce the
  chances of pregnancy
• Lesny, et al., Hum Reprod, 1998

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Touching the fundus

• Yes 24 PR
• No 46 PR
• Waterstone, et al., Lancet, 1991

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Touching the fundus

• Distance between the tip of the catheter and the
  uterine fundus
• 10 mm 20.6
• 15 mm 31.3
• 20 mm 33.3 implantation rate
• Coroleu, et al., Lancet, 1991

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Gentle manipulation

• Gentle manipulation should be the rule even in
  introducing the speculum to avoid unnecessary
  pushing of the cervix.
• Studies have shown that technically difficult
  embryo transfers are associated with reduced
  pregnancy rates
• Sharif, et al., Hum Reprod, 1995

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Gentle manipulation

• Some authors suggest that it is preferable to
  wait for the release of embryos from the catheter
  or to wait before withdrawal of the catheter.
• Wisanto, et al., Fertil Steril, 1989
• It was reported no differences in the pregnancy
  rate between withdrawal of the catheter
  immediately after embryo deposit or after a 30 s
  wait
• Martinez, et al., Hum Reprod, 2001

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Blood

• When blood was noted outside the transfer
  catheter, the chance of conception was reduced
  significantly by sixfold to sevenfold
• Goudas, et al., Fertil Steril, 1998

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Ultrasound Guidance

• The full bladder required to perform
  transabdominal ultrasound examinations is itself
  helpful in straightening the cervico-uterine axis
  and improving pregnancy rates
• Lewin et al., J Assisted Reprod Genet, 1987

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Ultrasound Guidance

• is especially helpful with the insertion of
  soft catheters. When placement is difficult,
  the problem may be visualized and modification of
  the angle between the cervix and uterus can be
  accomplished with manipulation of the speculum.

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Ultrasound Guidance

• Better pregnancy rate
• Wood, et al., Hum Reprod, 2000
• Coroleu, et al., Hum Reprod, 2000
• No significant difference
• Al-Shawaf, et al., J Assisted Reprod Genet,
  1993
• Kan, et al., Hum Reprod, 1999

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Meta-analysis of ultrasound-guided ET
Buckett, Fertil Steril, 2003
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Bedrest

• Standing shortly after embryo transfer does not
  play a significant role in the final position of
  the embryos.
• Woolcott, et al., Hum Reprod, 1998
• In a study that had gt 1000 cycles the results
  strongly suggested that bedrest was not necessary
  following embryo transfer
• Sharif, et al., Fertil Steril, 1998

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Protocol for ET

• Full bladder, US guidance
• Wash cervix and lavage with culture media
• Trial transfer to internal os
• Wallace catheter, 30µl continious column
• Gentle insertion manipulate cervix with
  speculum
• Examination of catheter following transfer for
  retained embryos

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The goal

• Atraumatic placement of the embryos 1.5 cm
  proximal to the fundus without pain, bleeding,
  trauma to the endometrium or embryos and with the
  absence of uterine contractions.