Scolaris Content Display Scolaris Content Display

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Figures and Tables -
Figure 1

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Figures and Tables -
Figure 2

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Forest plot of comparison: 1 Live birth rate, outcome: 1.1 Live birth per couple.
Figures and Tables -
Figure 3

Forest plot of comparison: 1 Live birth rate, outcome: 1.1 Live birth per couple.

Forest plot of comparison: 2 Clinical pregnancy rate, outcome: 2.1 clinical pregnancy rate per couple.
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Figure 4

Forest plot of comparison: 2 Clinical pregnancy rate, outcome: 2.1 clinical pregnancy rate per couple.

Forest plot of comparison: 3 Cumulative pregnancy rate, outcome: 3.1 cumulative pregnancy rate from fresh and frozen transfers.
Figures and Tables -
Figure 5

Forest plot of comparison: 3 Cumulative pregnancy rate, outcome: 3.1 cumulative pregnancy rate from fresh and frozen transfers.

Funnel plot of comparison: 1 Live birth rate, outcome: 1.1 Live birth per couple.
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Figure 6

Funnel plot of comparison: 1 Live birth rate, outcome: 1.1 Live birth per couple.

Funnel plot of comparison: 2 Clinical pregnancy rate, outcome: 2.1 clinical pregnancy rate per couple.
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Figure 7

Funnel plot of comparison: 2 Clinical pregnancy rate, outcome: 2.1 clinical pregnancy rate per couple.

Comparison 1 Live birth rate, Outcome 1 Live birth per couple.
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Analysis 1.1

Comparison 1 Live birth rate, Outcome 1 Live birth per couple.

Comparison 1 Live birth rate, Outcome 2 Live birth per couple: grouped by number of embryos transferred.
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Analysis 1.2

Comparison 1 Live birth rate, Outcome 2 Live birth per couple: grouped by number of embryos transferred.

Comparison 1 Live birth rate, Outcome 3 Live birth rate per couple: grouped by prognosis.
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Analysis 1.3

Comparison 1 Live birth rate, Outcome 3 Live birth rate per couple: grouped by prognosis.

Comparison 1 Live birth rate, Outcome 4 Live birth rate: grouped by day of randomisation.
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Analysis 1.4

Comparison 1 Live birth rate, Outcome 4 Live birth rate: grouped by day of randomisation.

Comparison 2 Clinical pregnancy rate, Outcome 1 clinical pregnancy rate per couple.
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Analysis 2.1

Comparison 2 Clinical pregnancy rate, Outcome 1 clinical pregnancy rate per couple.

Comparison 2 Clinical pregnancy rate, Outcome 2 clinical pregnancy rate per couple: grouped by number of embryos transferred.
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Analysis 2.2

Comparison 2 Clinical pregnancy rate, Outcome 2 clinical pregnancy rate per couple: grouped by number of embryos transferred.

Comparison 2 Clinical pregnancy rate, Outcome 3 clinical pregnancy rate per couple: grouped by prognosis.
Figures and Tables -
Analysis 2.3

Comparison 2 Clinical pregnancy rate, Outcome 3 clinical pregnancy rate per couple: grouped by prognosis.

Comparison 2 Clinical pregnancy rate, Outcome 4 clinical pregnancy rate per couple: grouped by day of randomisation.
Figures and Tables -
Analysis 2.4

Comparison 2 Clinical pregnancy rate, Outcome 4 clinical pregnancy rate per couple: grouped by day of randomisation.

Comparison 3 Cumulative pregnancy rate, Outcome 1 cumulative pregnancy rate from fresh and frozen transfers.
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Analysis 3.1

Comparison 3 Cumulative pregnancy rate, Outcome 1 cumulative pregnancy rate from fresh and frozen transfers.

Comparison 4 Multiple‐pregnancy rate, Outcome 1 multiple‐pregnancy rate per couple.
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Analysis 4.1

Comparison 4 Multiple‐pregnancy rate, Outcome 1 multiple‐pregnancy rate per couple.

Comparison 4 Multiple‐pregnancy rate, Outcome 2 multiple‐pregnancy rate per couple: grouped by number of embryo transfer.
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Analysis 4.2

Comparison 4 Multiple‐pregnancy rate, Outcome 2 multiple‐pregnancy rate per couple: grouped by number of embryo transfer.

Comparison 4 Multiple‐pregnancy rate, Outcome 3 multiple‐pregnancy rate per couple: grouped by prognosis.
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Analysis 4.3

Comparison 4 Multiple‐pregnancy rate, Outcome 3 multiple‐pregnancy rate per couple: grouped by prognosis.

Comparison 4 Multiple‐pregnancy rate, Outcome 4 high order pregnancies (more than 2 gestational sacs) per couple.
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Analysis 4.4

Comparison 4 Multiple‐pregnancy rate, Outcome 4 high order pregnancies (more than 2 gestational sacs) per couple.

Comparison 4 Multiple‐pregnancy rate, Outcome 5 high order pregnancy: grouped by number of embryos transferred.
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Analysis 4.5

Comparison 4 Multiple‐pregnancy rate, Outcome 5 high order pregnancy: grouped by number of embryos transferred.

Comparison 4 Multiple‐pregnancy rate, Outcome 6 high order pregnancies: grouped by prognosis.
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Analysis 4.6

Comparison 4 Multiple‐pregnancy rate, Outcome 6 high order pregnancies: grouped by prognosis.

Comparison 4 Multiple‐pregnancy rate, Outcome 7 multiple‐pregnancy rate per pregnancy.
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Analysis 4.7

Comparison 4 Multiple‐pregnancy rate, Outcome 7 multiple‐pregnancy rate per pregnancy.

Comparison 4 Multiple‐pregnancy rate, Outcome 8 high order pregnancies per total pregnancies.
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Analysis 4.8

Comparison 4 Multiple‐pregnancy rate, Outcome 8 high order pregnancies per total pregnancies.

Comparison 5 Miscarriage rate, Outcome 1 miscarriage rate per couple.
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Analysis 5.1

Comparison 5 Miscarriage rate, Outcome 1 miscarriage rate per couple.

Comparison 5 Miscarriage rate, Outcome 2 miscarriage rate per pregnancy.
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Analysis 5.2

Comparison 5 Miscarriage rate, Outcome 2 miscarriage rate per pregnancy.

Comparison 6 Embryo freezing rate, Outcome 1 embryo freezing per couple.
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Analysis 6.1

Comparison 6 Embryo freezing rate, Outcome 1 embryo freezing per couple.

Comparison 6 Embryo freezing rate, Outcome 2 Embyro freezing per couple: grouped by number of embryos transferred.
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Analysis 6.2

Comparison 6 Embryo freezing rate, Outcome 2 Embyro freezing per couple: grouped by number of embryos transferred.

Comparison 6 Embryo freezing rate, Outcome 3 Embryo freezing per couple: grouped by prognostic factors.
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Analysis 6.3

Comparison 6 Embryo freezing rate, Outcome 3 Embryo freezing per couple: grouped by prognostic factors.

Comparison 7 Failure to transfer embryos rate per couple, Outcome 1 Failure to transfer any embryos per couple.
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Analysis 7.1

Comparison 7 Failure to transfer embryos rate per couple, Outcome 1 Failure to transfer any embryos per couple.

Comparison 7 Failure to transfer embryos rate per couple, Outcome 2 Failure to transfer any embryos per couple: grouped by prognostic factors.
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Analysis 7.2

Comparison 7 Failure to transfer embryos rate per couple, Outcome 2 Failure to transfer any embryos per couple: grouped by prognostic factors.

Comparison 7 Failure to transfer embryos rate per couple, Outcome 3 Failure to transfer any embryos per couple: grouped by number of embryos transferred.
Figures and Tables -
Analysis 7.3

Comparison 7 Failure to transfer embryos rate per couple, Outcome 3 Failure to transfer any embryos per couple: grouped by number of embryos transferred.

Table 1. Culture techniques of included studies

Trial

Culture Tech Day 2/3

Culture Tech Day 5/6

Brugnon 2010

G series™ medium (Vitrolife, Sweden)

G series™ medium (Vitrolife, Sweden)

Bungum 2003

Sequential G1 VItrolife

Sequential G1/G2 Vitrolife

Coskun 2000

Sequential Medicult

Sequential G1/G2 Vitrolife

Devreker 2000

NS

NS

Elgindy 2011

NS

NS

Emiliani 2003

In‐house sequential (based on G1/G2)

In‐house sequential (based on G1/G2)

Fisch 2007

Frattarelli 2003

Sequential NS

Sequential NS

Gardner 1998a

Single Hams F10 In‐house

Sequential G1/G2 In‐house

Hreinsson 2004

Vitro life IVF

Sequential G1/G2 or CCM Vitrolife

Karaki 2002

Medicult

Sequential G1/G2 Vitrolife

Kolibianakis 2004

Sequential G1 Vitrolife

Sequential G1/G2 Vitrolife

Levitas 2004

NS

Sequential ‐ G1/G2 Vitrolife

Levron 2002

NS

NS

Livingstone 2002

Sequential ‐ Sydney IVF Cook

Sequential ‐ Sydney IVF Cook

Motta 1998

Sequential ‐ Irvines P1

Sequential ‐ Irvines P1 then Blast media

Pantos 2004

Papanikolaou 2005

Sequential ‐ Vitrolife G1/G2 GII or GIII

Sequential ‐ Vitrolife G1/G2 GII or GIII

Papanikolaou 2006

Assume Sequential ‐ Vitrolife G1/G2

Assume Sequential ‐ Vitrolife G1/G2

Rienzi 2002

Sequential G1 Vitrolife

Sequential G1/G2 Vitrolife

Schillaci 2002

NS

NS

Ten 2011

NS

NS

Van der Auwera 2002

Sequential both Cook and Vitrolife

Sequential both Cook and Vitrolife

Figures and Tables -
Table 1. Culture techniques of included studies
Table 2. Blastocyst and implantation rate (in Day 5 to 6 transfers)

Study

Blastocyst rate

Implantation D2/3

Implantation D5/6

Other

Brugnon 2010

Not stated

24/52 46.2%

23/55 41.8%

Bungum 2003

55.2%

50/114 43.9%

44/120 36.7%

2/61 patients had only 1 blastocyst

Coskun 2000

28%

50/235 21.3%

52/218 23.9%

77% patients had at least 1 blastocyst

Devreker 2000

Not stated

1/34 2.9%

8/19 42.1%

Elgindy 2011

97%

71/197 36%

53/280 19%

Emiliani 2003

48%

57/197 28.9%

50/168 29.8%

Fisch 2007

Not stated

11/12 92%

4/8 50%

Frattarelli 2003

Not stated

18/69 26.1%

23/53 43.4%

Gardner 1998

46.5%

64/174 36.8%

53/95 55.8%

85% patients had at least 2 blastocysts

Hreinsson 2004

33%

29/139 20.9%

24/114 21.1%

2 morula replace (one implanted). 60% preg rate when top quality blasts transferred

Karaki 2002

33%

37/291 12.7%

37/142 26.1%

9/80 cancelled due to lack of blastocysts (unselected)

Kolibiankis 2004

50.7%

96/234 41.0%

94/226 41.6%

Levitas 2004

43%

4/56 7.1%

10/24 4.2%

Day 5‐7 26% cancelled due to lack of blastocysts (poor prog)

Levron 2002

34.2%

53/137 38.7%

20/99 20.2%

6.5% cancelled due to lack of blastocysts (good prog)

Livingstone 2002

not stated

Motta 1998

Not stated

51/262 19.5%

36/120 30.0%

6/58 cycles cancelled D5 no blastocysts

Pantos 2004

44.6%

15.8%

15.8%

Papanikolaou 2005

Not stated

35/170 20.6%

59/158 37.3%

4/158 women had only 1 blast transferred due to lack of availability and 1 had it on request.

Papanikolaou 2006

Not stated

38/156 24%

58/149 38.9%

Number of patients with no embryos avail D3: 8 and D5: 11

Rienzi 2002

44.8%

34/96 35.4%

38/100 38.0%

Good prognosis

Schillaci 2002

60.3%

23/168 13.7%

26/110 23.6%

Unselected population nil cancellations D5

Ten 2011

Not stated

21/54 38.9%

26/56 46.4%

Good prognosis

Van der Auwera

44.7%

31/106 29.2%

41/90 45.6%

27% cancellation D5 (unselected population)

Figures and Tables -
Table 2. Blastocyst and implantation rate (in Day 5 to 6 transfers)
Table 3. Mean number of embryos transferred

Study ID

Day 2/3

Day 5/6

Brugnon 2010

1

1

Bungum 2003

2.00

1.97

Coskun 2000

2.3

2.2

Devreker 2000

2.83

1.73

Elgindy 2010

2.8

1.97

Emiliani 2003

2.1

1.9

Fisch 2007

1

1

Frattarelli 2003

2.96

2.04

Gardner 1998

3.7

2.2

Hreinsson J

1.8

1.9

Karaki 2002

3.5

2.0

Kolibiankis 2004

1.9

1.8

Levitas 2004

3.4

1.9

Levron 2002

3.1

2.3

Livingstone

2.0

1.0

Motta 1998

4.6

2.3

Pantos 2004

4

3.4

Papanikolaou 2005

2

1.97

Papanikolaou 2006

1

1

Rienzi 2002

2.0

2.0

Schillaci 2002

2.8

1.8

Ten 2011

2

2

Van der Auwera 2002

1.86

1.87

Figures and Tables -
Table 3. Mean number of embryos transferred
Comparison 1. Live birth rate

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Live birth per couple Show forest plot

12

1510

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.40 [1.13, 1.74]

2 Live birth per couple: grouped by number of embryos transferred Show forest plot

12

Peto Odds Ratio (Peto, Fixed, 95% CI)

Subtotals only

2.1 more cleavage stage than blastocyst embyros transferred

6

483

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.52 [1.03, 2.23]

2.2 single embryo transfer

2

458

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.46 [0.98, 2.19]

2.3 equal number of embryos transferred

6

1027

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.35 [1.04, 1.75]

3 Live birth rate per couple: grouped by prognosis Show forest plot

12

1510

Odds Ratio (M‐H, Random, 95% CI)

1.37 [1.01, 1.85]

3.1 good prognostic factors

8

1126

Odds Ratio (M‐H, Random, 95% CI)

1.43 [0.99, 2.07]

3.2 poor prognostic factors

2

77

Odds Ratio (M‐H, Random, 95% CI)

1.99 [0.49, 8.04]

3.3 unselected group

2

307

Odds Ratio (M‐H, Random, 95% CI)

1.05 [0.56, 1.97]

4 Live birth rate: grouped by day of randomisation Show forest plot

12

1510

Odds Ratio (M‐H, Random, 95% CI)

1.37 [1.01, 1.85]

4.1 randomisation at start of cycle

5

819

Odds Ratio (M‐H, Random, 95% CI)

1.25 [0.90, 1.73]

4.2 randomised on day of OPU and day 1 after OPU

3

245

Odds Ratio (M‐H, Random, 95% CI)

0.97 [0.37, 2.58]

4.3 randomised Day 2 to 3 post OPU

2

364

Odds Ratio (M‐H, Random, 95% CI)

2.17 [1.42, 3.33]

4.4 day of randomisation unstated

2

82

Odds Ratio (M‐H, Random, 95% CI)

1.68 [0.65, 4.38]

Figures and Tables -
Comparison 1. Live birth rate
Comparison 2. Clinical pregnancy rate

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 clinical pregnancy rate per couple Show forest plot

23

3241

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.14 [0.99, 1.32]

2 clinical pregnancy rate per couple: grouped by number of embryos transferred Show forest plot

23

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

2.1 equal numbers of ET

11

1854

Odds Ratio (M‐H, Fixed, 95% CI)

1.19 [0.99, 1.44]

2.2 more cleavage stage than blastocyst embryos transfered

12

1387

Odds Ratio (M‐H, Fixed, 95% CI)

1.07 [0.86, 1.33]

2.3 Single embryo transfer

3

478

Odds Ratio (M‐H, Fixed, 95% CI)

1.24 [0.84, 1.82]

3 clinical pregnancy rate per couple: grouped by prognosis Show forest plot

23

3241

Odds Ratio (M‐H, Random, 95% CI)

1.13 [0.92, 1.40]

3.1 Good prognostic factors

14

1756

Odds Ratio (M‐H, Random, 95% CI)

1.15 [0.83, 1.58]

3.2 Poor prognostic factors

2

77

Odds Ratio (M‐H, Random, 95% CI)

2.59 [0.75, 8.92]

3.3 Unselected group

7

1408

Odds Ratio (M‐H, Random, 95% CI)

1.01 [0.81, 1.25]

4 clinical pregnancy rate per couple: grouped by day of randomisation Show forest plot

23

3241

Odds Ratio (M‐H, Fixed, 95% CI)

1.14 [0.99, 1.32]

4.1 Randomised start of cycle

7

1371

Odds Ratio (M‐H, Fixed, 95% CI)

1.19 [0.95, 1.49]

4.2 Randomised on day of OPU or day 1

8

892

Odds Ratio (M‐H, Fixed, 95% CI)

1.00 [0.76, 1.31]

4.3 Randomised on day 2 to 3

4

537

Odds Ratio (M‐H, Fixed, 95% CI)

1.59 [1.13, 2.23]

4.4 Day of randomisation unstated

4

441

Odds Ratio (M‐H, Fixed, 95% CI)

0.84 [0.57, 1.25]

Figures and Tables -
Comparison 2. Clinical pregnancy rate
Comparison 3. Cumulative pregnancy rate

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 cumulative pregnancy rate from fresh and frozen transfers Show forest plot

4

527

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.58 [1.11, 2.25]

Figures and Tables -
Comparison 3. Cumulative pregnancy rate
Comparison 4. Multiple‐pregnancy rate

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 multiple‐pregnancy rate per couple Show forest plot

16

2481

Peto Odds Ratio (Peto, Fixed, 95% CI)

0.92 [0.71, 1.19]

2 multiple‐pregnancy rate per couple: grouped by number of embryo transfer Show forest plot

16

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

2.1 Equal number of embryos transferred

8

1672

Odds Ratio (M‐H, Fixed, 95% CI)

1.05 [0.75, 1.46]

2.2 More cleavage stage than blastocyst embryos transferred

8

809

Odds Ratio (M‐H, Fixed, 95% CI)

0.75 [0.49, 1.13]

2.3 Single embryo transfer

1

351

Odds Ratio (M‐H, Fixed, 95% CI)

0.20 [0.01, 4.17]

3 multiple‐pregnancy rate per couple: grouped by prognosis Show forest plot

16

2481

Odds Ratio (M‐H, Fixed, 95% CI)

0.91 [0.70, 1.18]

3.1 Good prognostic factors

11

1498

Odds Ratio (M‐H, Fixed, 95% CI)

0.88 [0.63, 1.22]

3.2 Poor prognostic factors

1

54

Odds Ratio (M‐H, Fixed, 95% CI)

0.89 [0.14, 5.81]

3.3 Unselected

4

929

Odds Ratio (M‐H, Fixed, 95% CI)

0.96 [0.62, 1.47]

4 high order pregnancies (more than 2 gestational sacs) per couple Show forest plot

12

2035

Odds Ratio (M‐H, Fixed, 95% CI)

0.44 [0.15, 1.33]

5 high order pregnancy: grouped by number of embryos transferred Show forest plot

12

2035

Odds Ratio (M‐H, Fixed, 95% CI)

0.44 [0.15, 1.33]

5.1 Equal number of embryos transferred

8

1672

Odds Ratio (M‐H, Fixed, 95% CI)

0.33 [0.01, 8.28]

5.2 More cleavage stage than blastocyst embryos transferred

4

363

Odds Ratio (M‐H, Fixed, 95% CI)

0.46 [0.14, 1.49]

6 high order pregnancies: grouped by prognosis Show forest plot

12

2035

Odds Ratio (M‐H, Fixed, 95% CI)

0.44 [0.15, 1.33]

6.1 Good prognostic factors

9

1385

Odds Ratio (M‐H, Fixed, 95% CI)

0.29 [0.08, 1.06]

6.2 Poor prognostic factors

1

54

Odds Ratio (M‐H, Fixed, 95% CI)

4.2 [0.16, 107.89]

6.3 Unselected

2

596

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

7 multiple‐pregnancy rate per pregnancy Show forest plot

14

Odds Ratio (M‐H, Fixed, 95% CI)

Totals not selected

8 high order pregnancies per total pregnancies Show forest plot

12

Odds Ratio (M‐H, Fixed, 95% CI)

Totals not selected

Figures and Tables -
Comparison 4. Multiple‐pregnancy rate
Comparison 5. Miscarriage rate

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 miscarriage rate per couple Show forest plot

14

2127

Peto Odds Ratio (Peto, Fixed, 95% CI)

1.14 [0.84, 1.55]

2 miscarriage rate per pregnancy Show forest plot

14

Odds Ratio (M‐H, Fixed, 95% CI)

Totals not selected

Figures and Tables -
Comparison 5. Miscarriage rate
Comparison 6. Embryo freezing rate

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 embryo freezing per couple Show forest plot

11

1729

Peto Odds Ratio (Peto, Fixed, 95% CI)

2.88 [2.35, 3.51]

2 Embyro freezing per couple: grouped by number of embryos transferred Show forest plot

11

1729

Odds Ratio (M‐H, Random, 95% CI)

4.06 [2.49, 6.60]

2.1 equal number of embryos transferred

7

1118

Odds Ratio (M‐H, Random, 95% CI)

4.35 [2.11, 8.97]

2.2 more cleavage stage than blastocyst embryos transferred

4

611

Odds Ratio (M‐H, Random, 95% CI)

3.95 [2.09, 7.46]

3 Embryo freezing per couple: grouped by prognostic factors Show forest plot

10

1486

Odds Ratio (M‐H, Random, 95% CI)

4.17 [2.41, 7.21]

3.1 good prognostic factors

6

612

Odds Ratio (M‐H, Random, 95% CI)

6.39 [3.12, 13.10]

3.2 poor prognostic factors

0

0

Odds Ratio (M‐H, Random, 95% CI)

0.0 [0.0, 0.0]

3.3 unselected

4

874

Odds Ratio (M‐H, Random, 95% CI)

2.60 [1.31, 5.16]

Figures and Tables -
Comparison 6. Embryo freezing rate
Comparison 7. Failure to transfer embryos rate per couple

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Failure to transfer any embryos per couple Show forest plot

16

2459

Odds Ratio (M‐H, Fixed, 95% CI)

0.35 [0.24, 0.51]

2 Failure to transfer any embryos per couple: grouped by prognostic factors Show forest plot

16

2459

Odds Ratio (M‐H, Fixed, 95% CI)

0.35 [0.24, 0.51]

2.1 good prognostic factors

9

1315

Odds Ratio (M‐H, Fixed, 95% CI)

0.67 [0.35, 1.27]

2.2 poor prognostic factors

2

77

Odds Ratio (M‐H, Fixed, 95% CI)

0.20 [0.04, 1.08]

2.3 unselected

5

1067

Odds Ratio (M‐H, Fixed, 95% CI)

0.27 [0.17, 0.43]

3 Failure to transfer any embryos per couple: grouped by number of embryos transferred Show forest plot

16

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

3.1 equal number of embryos transferred

7

1321

Odds Ratio (M‐H, Fixed, 95% CI)

0.37 [0.23, 0.61]

3.2 more cleavage stage than blastocyst embryos tranferred

8

787

Odds Ratio (M‐H, Fixed, 95% CI)

0.23 [0.11, 0.46]

3.3 single embryo transfer

1

351

Odds Ratio (M‐H, Fixed, 95% CI)

0.71 [0.28, 1.81]

Figures and Tables -
Comparison 7. Failure to transfer embryos rate per couple