Research

A large body of recent research supplies the background and supporting data for the information on this website. It spans a broad range of professional and academic work.

 

Anti-oestrogens (Clomid)

 

Benefits of single embryo transfer (SET)

  • One Child at a Time, Report of the Expert Group on Multiple Births after IVF, October 2006, p34, para 11.2.1. PDF. Download the pdf.
  • Thurin et al. Elective single-embryo-transfer versus double embryo transfer in IVF New England Journal of Medicine 2004; 351: 2392–2402. Download the abstract. 
  • Khalaf Y, El-Toukhy T, Coomarasamy A, Kamal A, Bolton V, Braude P (2008). Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study BJOG: An International Journal of Obstetrics and Gynaecology 115 (3), 385–390 doi:10.1111/j.1471–0528.2007.01584.x. Read the study. 

Bringing up twins

 

Chances of success with single embryo transfer (SET)

  • Khalaf Y, El-Toukhy T, Coomarasamy A, Kamal A, Bolton V, Braude P (2008). Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study BJOG: An International Journal of Obstetrics and Gynaecology 115 (3), 385–390 doi:10.1111/j.1471–0528.2007.01584.x. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2253713

Return to top


Embryo grading

Embryo transfer: 2–3 day (cleavage stage)

  • Chitayat D and Hall JG. Genetic aspects of twinning in: Multiple Pregnancy Kilby M et al (eds), RCOG 2006.
  • HFEA statistics for year 2005 collected from the HFEA Register 2005: Because definitive information on the developmental stage of transferred embryos has only recently started being collected, all relevant information has been inferred based on the number of days incubation.
  • Khalaf Y, El-Toukhy T, Coomarasamy A, Kamal A, Bolton V, Braude P (2008). Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study BJOG: An International Journal of Obstetrics and Gynaecology 115 (3), 385–390 doi:10.1111/j.1471–0528.2007.01584.x. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2253713
  • Kurinczuk, J. Epidemiology of multiple pregnancy: changing effects of assisted conception in: Multiple Pregnancy Kilby M et al (eds) RCOG 2006.
  • HFEA register data (2005) based on 38,264 cycles given to 29,688 women between 1 April 2003 and 31 March 2004, leading to 8,251 births and 10,242 children born.

 

Embryo transfer: 5–6 day (blastocyst stage)


FAQs–patients

Return to top

FAQs–professionals

 

Gamete intra-fallopian transfer (GIFT)

  • HFEA register for the years 1993–2006 gives a multiple birth rate of 26.2% for all GIFT births. Data from UK clinics, collected in 2007, gives multiple birth rates ranging from 8.7% to 45.5%. Figures from Australia showed a similar discrepancy, with the multiple birth rate ranging from 9.4% to 24.3%.
  • HFEA Code of Practice for clinics, para 8.5.1: Risks: number of eggs or embryos to transfer. http://cop.hfea.gov.uk/cop/

 

Hormone treatment

 

In vitro fertilisation (IVF)

Return to top

Risks to the child

  • Blickstein I. Epidemiology of cerebral palsy in multiple pregnancies in: Multiple Pregnancy Kilby M et al (eds), RCOG 2006.
  • Bryan, E. The impact of multiple preterm births on the family BJOG 2003; 110: 24–28. Abstract at http://www3.interscience.wiley.com/journal/118854542/abstract
  • Colpin, H et al. Parenting stress and psychosocial well-being among parents with twins conceived naturally or by reproductive technology Human Reproduction 1999; 14: 3133–3137. http://humrep.oxfordjournals.org/cgi/content/full/14/12/3133
  • Cook R et al. A preliminary study of parental stress and child behaviour in families with twins conceived by in-vitro fertilisation Human Reproduction 1998; 13: 3244–3246. PDF at http://humrep.oxfordjournals.org/cgi/reprint/13/11/3244.pdf
  • Costeloe, K et al. The EPICure study: outcomes to discharge from hospital for infants born at the threshold of viability. Pediatrics 2000; 106: 659–671. http://pediatrics.aappublications.org/cgi/content/full/106/4/659
  • D´Alton, M. Infertility and the desire for multiple births, Fertility and Sterility 2004 81(3) 523–525.
  • Ellison, M et al. Psychosocial risks associated with multiple births resulting from assisted reproduction Fertility and Sterility 2005; 83: 1422–1428. Abstract at http://www.ncbi.nlm.nih.gov/pubmed/15866579?dopt=Abstract
  • ESHRE Task Force on Ethics and Laws, Ethical Issues related to multiple pregnancies in medically assisted reproduction. 2003; 18(9): 1976–1979. http://humrep.oxfordjournals.org/cgi/content/full/18/9/1976
  • Glazebrook, C et al. Parenting stress in first-time mothers of twins and triplets conceived after in vitro fertilization Fertility and Sterility 2004; 81: 505–511. Abstract at http://www.ncbi.nlm.nih.gov/pubmed/15037391?dopt=Abstract
  • Klock, SC. Psychosocial adjustment to twins after infertility Best Practice and Research Clinical Obstetrics and Gynaecology 2004; 18: 645–656. Abstract at http://www.ncbi.nlm.nih.gov/pubmed/15279823?dopt=Abstract
  • Kurinczuk, JJ. Epidemiology of multiple pregnancy: changing effects of assisted conception in: Multiple pregnancy Kilby, M et al. (eds) RCOG 2006-07-07 and Sebire, NJ Anomalous development in twins (including monozygotic duplication) in: ibid.
  • Marlow, N. Does neonatal and infant neurodevelopment of twins and singletons differ? in: Multiple Pregnancy Kilby M et al (eds) RCOG 2006. According to Marlow, any possible small effect of twinning on developmental progress will be swamped by the serious sequelae of very preterm birth often endured by twins.
  • Moser K, Macfarlane A, Chow YH, Hilder L, Dattani N. Introducing new data on gestation-specific infant mortality among babies born in 2005 in England and Wales. Health Statistics Quarterly, Autumn 2007; 13–27. Abstract at http://www.ncbi.nlm.nih.gov/pubmed/17894197
  • Oakley, L and Doyle P. Predicting the impact of in vitro fertilisation and other forms of assisted conception on perinatal and infant mortality in England and Wales: examining the role of multiplicity BJOG 2006; 113: 738–741. Abstract at http://www3.interscience.wiley.com/journal/118613397/abstract. Updated to 2003 figures through personal correspondence with the authors.
  • Olivennes, F et al. Behavioural and cognitive development as well as family functioning of twins conceived by assisted reproduction: findings from a large population study. Fertility and Sterility 2005; 84:725–733. Abstract at http://www.ncbi.nlm.nih.gov/pubmed/16169409?dopt=Abstract
  • Ombelet et al. Human Reproduction 2006; 21: 1025–1032.
  • One Child at a Time, Report of the Expert Group on Multiple Births after IVF, October 2006, p8. PDF at http://www.hfea.gov.uk/docs/MBSET_report_Final_Dec_06.pdf
  • Ostfeld, BM et al. Maternal behaviour toward premature twins: implications for development Twin Research 2000; 3: 234–241. http://www.atypon-link.com/AAP/doi/pdf/10.1375/twin.3.4.234?cookieSet=1
  • Pinborg, A. et al. Morbidity in a Danish National cohort of 472 IVF/ICSI twins, 1132 non-IVF/ICSI twins and 634 IVF/ICSI singletons: health-related and social implications for the children and their families. Human Reproduction 2003; 18(6): 1234–1243. http://humrep.oxfordjournals.org/cgi/content/full/18/6/1234
  • Pinborg, A. IVF/ICSI twin pregnancies: risks and prevention Human Reproduction Update 2005; 11: 575–593. http://humupd.oxfordjournals.org/cgi/content/full/11/6/575
  • The Practice Committee of the American Society for Reproductive Medicine, Multiple pregnancy associated with infertility therapy, Fertility and Sterility 2004, 82, Suppl 1, S153–157. 
  • Topp et al Acta Obstetrics and Gynaecology Scandinavia 2004; 83: 548–553.
  • Yokoyama Y, Shimizu T and Hayakawa K (1995). Incidence of handicaps in multiple births and associated factors. Acta Genet Med Gemellol (Roma) 44, 81–91. Abstract at http://www.ncbi.nlm.nih.gov/pubmed/8750772.

Risks to the mother

Return to top

Stimulated intrauterine insemination (IUI)

  • Guzick DS, Carson SA, Coutifaris C, Overstreet JW, Factor-Litvak P, Steinkampf MP, et al. Efficacy of superovulation and intrauterine insemination in the treatment of infertility. National Cooperative Reproductive Medicine Network. N Engl J Med 1999;340:177–83. https://content.nejm.org/cgi/content/full/340/3/177
  • NICE (p78 of CG011 Full Guideline): ´The multiple birth rates for twins, triplets and quadruplets were 22%, 4% and 3%, respectively, in the stimulated IUI group and there were no multiple births in the unstimulated group.´ (US study.) PDF download from http://www.nice.org.uk/guidance/index.jsp?action=download&o=29269
  • Nyboe Anderson A et al. Human Reproduction (2007).

 

What other countries are doing

 

Which patients are suitable for single embryo transfer (SET)?

 

Why should I recommend single embryo transfer (SET)?

Return to top