Embryo assessment and clinical outcome

Embryo assessment is a crucial component to the clinical success of IVF techniques.

Selection of the most competent embryo(s) for transfer based on morphological criteria is not sufficient.

Many women fail to achieve an ongoing pregnancy even after transfer of good quality embryos.

One of the presumed causes is that such morphologically normal embryos show aneuploidies.

Aneuploidies are the major fators causing low pregnancy rates and high miscarriage rates in IVF.

Pilot study PGS by aCGH on “good prognosis” patients.

Aim of the stydy:

v We aimed to explore the usefulness of offering array-CGH based PGS to good prognosis patients, usually not considered an indication for testing.

Study design:

＊ ICSI procedure;

＊ blastocyst biopsy on day 5;

＊ PGS by array-CGH;

＊ fresh single embryo transfer on Day 6.

Inclusion criteria:

＊ Female patients aged<35;

＊ no prior IVF treatment.

Pilot study PGS by aCGH on “good prognosis” patientsClinical results

PGS Clinical data Total %

No. of cycles 64

Age(average) 33.7±1.1

No. of embryos analysed 246

Mean per cycle 3.8

No. of embryos diagnosed(%) 241 98.0%

No. of embryos with diagnosis failure 5 2.0%

No. of aneuploid embryos(%) 119 49.4%

No. of embryos transferred 61

Mean embryos transferred 1.1

No. of transfers(%) 58 90.6%

No. +HCG(%) 42 74.1%

No of biochemical pregnancies 2

No. of early miscarriages(<12 weeks) 0 0.0%

No.of ongoing Clinical pregnancles(%ET) 40 69.0%

No. of Fetal Sacs 40

No.of Fetal Hearth Beat(FHB) 40

Ongoing Implantation rate(%ET) 65.6%

• Age related increase in aneuploid gestations is well established.

• These data are based on clinically recognized pregnancies.

• Trends are likely true, but these data reflect only those abnormalities which allow ongoing development to the clinical stage.

• For example, would iargely exclude autosomal monosomies and many of the trisomies as well.

• Likely a gross under-representation of the impact of embryonic aneuploidy on human reproduction.

Conclusion

• Multi-center data (n>2000 patients) using PGS v.1 or PGS v.2 with regular stimulation shows same euploidy rates irrespective of cohort size.

• PGS v.2 signficantly improves pregnancy outcomes: Therefore it is desirable to produce higher mumber of euploid embryos.

• Euploid embryos implant at the same rate at any age: Embryo banking in older patients achieves pregnancy in a shorter period of time, when time is of the essence.

Overvien

The incidence of aneuploidy.

Literature review in order to address to the following question:

Is a higher oocyte yield associated with an increased aneuploidy rate?

Is the incidence of aneuploidy in embryos may be affected by ovarian stimulation regimens used in IVF?

Retrospective analysis of data from PGS cycles by array-CGH to determine the chomosome error rate detected after of different number of oocyte retrieved.

IVF –what is the clinical issue?

%aneuploidy in embryos increases with maternal age

Advantages

• Less patient “fatigue” : less drop out from cycle to cycle.

• Cheaper PGD : One fee per package of IVF cycles.

• Facilitates “guaranteed baby” plans.

aCGH advantages

• All 24 chromosome aneuploidies and translocations detected.

• Results in <16 hours:

allows for day 5 biopsy and 10am day 6 transfer.• Parental DNA not required : ad hoc decisions

possible.• ICSI not required.• Standard of care in postnatal genetics and soon

prenatal.

Should PGS be offeredto all IVF patients?

Embryo banking for older patients

Clinical application of comprehensive chromosomal screening at the blastocyst stage

• 45 infertile couples with at least one previous unsuccessful IVF treatment cycle (mean2.4)

• DAY 5 trophectoderm cell biopsy+ CGH

• Diagnosis in 93.7%

• Aneuploidy rate 51.3%

• Implantation rate68.9%

• Pregnancy rate 82.2%

CGH.blastocyst biopsy and vitrification:clinical results

Cycles Mat.age

Prev.failedcycles

embryosreplaced

implant.(+sac)

CGH:

Control:

45

113

37.7

37.1

2.4

12

2.0

2.7

72％

46％p=0.0003

Schoolcraft et al.(2010) Fertil.94:1700

Prospective Randomized Trial in patients

<35 with day 5 biopsy,day 6 transfer Control PGD(aCGH)

Patients 48 55

Maternal age <35 <35

Biopsy on days No Yes

Transfer on Day6 Day6

Embryos euploid (N) n/a 53.2%(425)

Embryos replaced (av.) 48 (1) 55 (1)

Pregnancy rate (sac) 45.8% 70.9%　 p<0.05

Ongoing prag rate 41.7% 69.1%　 p<0.05

Mulitple pregnancies 0 0

Yong et al. (2012) Molec Reprod

Why cohort size matters？• Cost:the lager the more drugs needed • Quality of embryos:does aneuploidy

changes with cohort size?• Absolute number of euploid

embryos:dose it increase with higher cohort sizes?

• Selection potential :the higher the absolute number of euploid embryos the better for PGD results

IVF results comparedto chromosome abnormalities

<35 35-37 38-40 41-42

Ongoing implantation(US average)* 31% 23% 13% 6%

Abnormal embryos(array CGH)* 54% 67% 75% 82%

Non-chromosomal implantation loss 15% 10% 12% 12%

*estimated from SART(2011)**Reprogenetics 2011 data

Fiorentino’s results

• Next presentation: An italian dataset shows increasing aneuploidy

rate with cohort size ,using array CGH.

• Hypothesis: Italian centers stimulate milder compared to US

due to the italian law. Large cohorts are not let to mature proterly? Is mild stimulation producing chromosome

abnormalities in large cohorts of embryos?

一條龍試管嬰兒 aCGH

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