FRESH OR FROZEN EMBYOS WHAT IS THE LATEST EVIDENCE ?

DR. ASMA MOMANI

CLEVELAND CLINIC , ANDROLOGY LAB

TRAINEE 2018

OBJECTIVES

• Hisory

• Indication of freezing embryos

• Slow freezing versus vitrification

• Advantages and disadvantages of fresh and frozen cycle

• Results

• Take home message

IDEA OF FREEZING

• - limited number of embyos we can transfer, what to do with

surplus embyos?

• - cancellation of ET ( Hyperstimulation, Unfavourable

endometrium)

• - Decrease cost on the couple

• - PGD ( especially blastocyst ,needs time until we get the result )

HISTORY

• 1949- first human gamete cryopreservation

• 1984- first live birth with FET

• 1985- first pregnancies with thawed blastocysts

Polge et al 1949, Zeilmaker et al 1984, Cohen et al 1985, Chen 1986

HOW FREEZING IS DONE?

• Store in liquid nitrogen at -196 C.

• To move the embryo from 37 C to -196c we need to use

cryoprotectants to prevent cold induced damage to the

cells, as a result of their exposure to low temperature.

• Cryoprotectants are of two types:

• 1) external: sucrose

2) internal: DMSO, ethyleneglycol

ADVANTAGES FOR VITRIFICATION AND FET

• Allows for better embryo/uterine synchrony

• Can be scheduled & planned

• Less stressful for the patient

• Equivalent or better pregnancy rates to fresh

ENDOMETRIAL RECEPTIVITY

•One of the primary causes cited a better result with

FET , was the adverse effect of ovarian stimulation on

Endometrial receptivity.

• The window of implantation is advanced SO

• Either : No lmplantion

• Adverse obstetric out come ( low birth weight,

PET )

UTERINE EXPRESS HAS LEFT THE STATION

FRESH VS FROZEN RISK COMPARISON IVF OUTCOME

When compared to fresh transfer, frozen-thawed transfer

has been associated with:

• Reduced risk of implantation failure in normal responders

• Reduced risk of implantation failure following premature

progesterone elevation

• Reduced risk of ivf failure per retrieval

Shapiro et al 2011, Shapiro et al 2010, Roque et al 2012.

RANDOMIZED TRIAL: FRESH VS FROZEN EMBRYOS

• 65% clinical pregnancy rate in fresh transfers

• 80% clinical pregnancy rate in frozen transfers

• Difference not statistically signicant (p=0.1109)

Shapiro et al 2011

META ANALYSIS CONCLUSION

• CONCLUSIONS:

• The freeze-all strategy could be favorable when high numbers of

oocytes are collected, signaling an association between higher

ovarian stimulation and consequent impairment of endometrial

receptivity. However, when the mean number of oocytes collected is

<15, the freeze-all strategy does not appear to be advantageous.

THE NEW TREND

• No fresh transfer at all!

• Electively freeze all embryos

• Transfer only in the next cycle

• Only balstocyst

• Only vitrification

NEED TO WORK TOWARDS THIS

• Gradual process

• Need to master the skills

• Develop confidence in your IVF labs!

• Training

• Monitoring

• Quality control

CONCLUSION

● Data indicates little, if any compromise to embryo

Viability with vitrification.

• ●Vitrification & FET may allow for better synchrony

between embryo & endometrium.

• ●Vitrification can match or exceed fresh embyos transfer

regarding pregnancy rates.

TAKE HOME MESSAGE

• Individualised approach is needed rather than “ freeze

all “ protocol .

• More randomised controlled trials are needed before

adopting “ freeze all “ protocol .

Thank you