1. Risk factors for monozygotic twinning after in vitro fertilization: a systematic review and meta-analysis 
Andrea Busnelli, M.D., Chiara Dallagiovanna, M.D., Marco Reschini, M.Sc., Alessio Paffoni, Ph.D., Luigi Fedele, M.D., Edgardo Somigliana, Ph.D. 
Fertility and Sterility 
Volume 111, Issue 2, Pages (February 2019)
DOI: /j.fertnstert
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

2. Figure 1 Embryo extended culture and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

3. Figure 2 Female age and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

4. Figure 3
Risk factors for monozygotic monochorionic twinning after IVF. (A) Embryo extended culture and risk of monozygotic monochorionic twinning. (B) Insemination method and risk of monozygotic monochorionic twinning. (C) Assisted hatching and risk of monozygotic monochorionic twinning. (D) Frozen-thawed embryo transfer and risk of monozygotic monochorionic twinning. (E) Female age and risk of monozygotic monochorionic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

5. Supplemental Figure 1 Flow diagram of study selection.
Fertility and Sterility  , DOI: ( /j.fertnstert )
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6. Supplemental Figure 2
Funnel plot with pseudo 95% confidence intervals of the estimate in 22 studies in which the risk of monozygotic twin (MZT) pregnancies in women undergoing blastocyst or cleavage-stage embryo transfer was evaluated. No indication of asymmetry was observed.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

7. Supplemental Figure 3
Assisted hatching and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

8. Supplemental Figure 4
Funnel plot with pseudo 95% confidence intervals of the estimate in 15 studies in which the risk of monozygotic twin (MZT) pregnancies in women undergoing assisted hatching was evaluated. No indication of asymmetry was observed.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

9. Supplemental Figure 5
Insemination method and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

10. Supplemental Figure 6
Embryo biopsy for preimplantation genetic testing for aneuploidies (PGT-A) or preimplantation genetic testing for monogenic/single-gene defects (PGT-M) and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

11. Supplemental Figure 7
Funnel plot with pseudo 95% confidence intervals of the estimate in four studies in which the risk of monozygotic twin (MZT) pregnancies in women undergoing embryo biopsy for preimplantation genetic testing for aneuploidies (PGT-A) or preimplantation genetic testing for monogenic/single-gene defects (PGT-M) was evaluated. No indication of asymmetry was observed.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

12. Supplemental Figure 8
Frozen-thawed embryos and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

13. Supplemental Figure 9
Funnel plot with pseudo 95% confidence intervals of the estimate in seven studies in which the risk of monozygotic twin (MZT) pregnancies in women undergoing frozen-thawed embryo transfer was evaluated. No indication of asymmetry was observed.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

14. Supplemental Figure 10
Funnel plot with pseudo 95% confidence intervals of the estimate in four studies in which the risk of monozygotic twin (MZT) pregnancies in women younger than 35 years was evaluated. No indication of asymmetry was observed.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions

15. Supplemental Figure 11
Oocytes donation and risk of monozygotic twinning.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2018 American Society for Reproductive Medicine Terms and Conditions