Embryo Transfer Prepared by: Dr.Yasmin Magdi Abd-Elkereem

Embryo Transfer • Final and most crucial step in ART in which

embryos are placed in female uterus.

• Close collaboration between clinician and embryologist.

• A successful transfer is a gentle and nontraumatic procedure.

• A number of studies have shown that significant improvements in clinical pregnancy rates can be achieved by giving due attention to ET technique.

(Fanchin et al. 1998)

Factors affecting embryo transfer

1. Implantation capacity of the embryo

2. Endometrial receptivity

3. Embryo Transfer technique

The Embryo• Failure of the embryo to implant is the major limiting step

determining Assisted Reproductive Techniques (ART) success rates.

• A number of strategies aimed at increasing the chance of embryo to successfully implant, such as

Preimplantation Genetic Diagnosis Assisted hatching Co-culture with human endometrial epithelial cells Embryo Glue

What is assisted hatching? creating an opening in Zona through which the embryonic cells can hatch out.

• The covering layer, or ‘shell’ surrounds embryos called the Zona Pellucida (ZP). The embryos have to “hatch” or break out of the zona in order to embed into the endometrium which lines the uterine cavity.

• Types : • Mechanical • Chemical • Lisar • Recommended in cases :-Thick or hard (ZP)-Age> 37 years-Previous implantation failurehistory for the case-Frozen embryo transfer -High FSH level of woman - Excess embryonic fragmentation

What is Embryo Glue ? Embryoglue is a 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.  This is a culture medium specially developed for the embryo transfer. • 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.

Media used in Embryo transfer are primarily based on the role of ions, amino acids, and we must focus on the role of different macromolecules in embryo culture media such as albumin and hyaluronan .

Albumin• highly abundant in the female

reproduction tract• source of energy• reservoir for the release of

hormones, vitamins, and metals.• Gives useful physical properties

of lubrication and viscosity• promotes ease of handling the

embryos• prevents its adherence to the

culture dish.• Source: patient’s own serum,

fetal cord serum, commercially pooled human serum albumin (HSA) and lately, recombinant human albumin (rHA).

hyaluronan (hyaluronic acid)• major glycosaminoglycans

present in the cervical mucus, the cumulus, follicular fluid, and seminal plasma

• increases up to the time of implantation (in Vivo)

• have an implantation-promoting effect

• Increases the viscosity• the adhesion and apposition

of embryo can be achieved faster

• Source: rooster comb or as a recombinant substance.

(Simon A, et all 2003) (Schoolcraft W,et all 2002)

The endometrium

• Uterine receptivity is defined as a restricted period when the uterus supports blastocyst attachment and this maternally driven ‘window’ of receptivity takes place from approximately day 19-24 in a normal menstrual cycle

(Wilcox et al. 1999;Navot et al. 1991)

Embryo Transfer Technique

Variables Influencing the Success of Embryo Transfer Technique

Laboratory Part 1. Embryo Selection

(Grade, Stage, no. and timing )

2.Handling of catheter 3.Embryo loaded method

of embryo in catheter 4. Check presence of

blood or mucus in/out catheter

5.Duration of embryo transfer technique

6. Embryo Loading medium

Clinician Part 1. The preparation before

embryo transfer 2. Transfer fashion (transfallopian (ZIFT),

transmyometrial and transcervical )

3.Uterine Contractions4. Fluid dynamics 5.Way of Catheter

Insertion 6.Placement of the

Catheter Tip7. Types of catheter

5.Embryo loaded method of embryo in catheter • Variations: • Volume of Media • constitution of the medium loaded in the

catheter • Loading with using fluid alone, or mixture of air

and fluid in the catheter• There are two common techniques in catheter loading : 1. Air loaded method 2.

Continuous fluid method

Types of Catheter • Mock transfer is very important to choose the type of the transfer catheter.

Variations are : • Stiff versus soft materials. • End and side openings. • Presence of an outer sheath. • Malleability. • Quality of the materials and finish.

• The benefit of one catheter over another is controversial. Wisanto et al. : The pregnancy rates difference : Frydman (32%), Wallace (19%), and TDT (19%).Al Shawaf et al. , Englert et al. : no difference : Frydman (31%) and the Wallace (30%).

Check presence of blood or mucus in/out catheter• The presence of blood on the outside of the

catheter tip :1..may be a sign of difficult embryo transfer2.associated with lower pregnancy rates3.a higher incidence of retained embryos.

• Mucus plugging of the catheter tip 1.can cause embryo retention and damage2.improper embryo placement3.affect the rate of embryo expulsion into the cervix.4. a source of contamination of the endometrial cavity and the embryos.

Goudas and colleagues.Fertil Steril 1998.

Visser et al. J Assist Reprod Genetics 1993.

Mansour et al.Hum Reprod 1994

• The embryo transfer catheter may be inserted in one of two ways: Blind insertion or with the aid of ultrasound guidance.

• Prapas et al. 1995,compared 61 ultrasound -guided embryo transfers with 71 blind insertions and described a significantly improved pregnancy rate with ultrasound (36.1% vs 22.6%).

• No Significant diffrence Al-Shawaf, et al. , J Assisted Reprod,1993 Kan, et al., Hum Reprod, 1999• Better Pregnancy Rate Wood, et al., Hum Reprod. , 2000 Coroleu, et al., Hum Reprod. , 2000

Way of Catheter Insertion

Trans-Vaginal Embryo TransferBlind Insertion

• The clinician feels the internal os and then either he advances the catheter till the fundus is felt and withdraw the catheter for 1 or 2 cm and position the embryos.

• Alternatively the clinician advances the inner catheter after feeling the resistance of the internal os by 3-4 cm based on previous measurement of the uterine cavity

• Based on Clinician Touch • inadvertent abutting of the

catheter tip

U.S guidance• The clinician use of abdominal

ultrasound in addition of visualizing the catheter is to straighten the uterovesical angle which my make the insertion of the catheter easier.

• Full bladder is required • facilitates the placement of soft

catheters• avoids touching the fundus• avoiding disruption of the

endometrium• plugging of the catheter tip with

endometrium, and the instigation of bleeding

• confirms that the catheter is beyond the internal os in cases of an elongated cervical canal

Thank You For contact: Yas.magdi@hotmail.com