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Multiple births in the United Kingdom – a consensus statement

The hazards of multiple pregnancy present the biggest risk to the health and welfare of children born as a result of in vitro fertilization (IVF). A comprehensive analysis of the consequences of multiple pregnancies has recently been published. The HFEA report produced by the Expert group on multiple births after IVF (http://www.hfea.gov.uk/en/483.html) has provided irrefutable evidence that the extraordinary rise in the prevalence of twin births in the UK is, in the main, due to fertility treatment, particularly IVF. Over 40,000 IVF cycles now take place in the UK each year, with average pregnancy rates following treatment now over 25% per cycle initiated. One in four pregnancies derived from IVF results in a twin birth – a tenfold increase in risk over natural conception. Given the major immediate and long-term consequences for women and, particularly, the children associated with twin birth, this level of demand on maternity, neonatal paediatric and child health services presents major problems for the statefunded health sector. A multiple pregnancy should not be regarded as the ideal outcome of IVF treatment. While two healthy babies may be born, twin pregnancies can result in adverse outcomes for both mother and child. With IVF-associated conceptions now accounting for in excess of 1% of UK births, the aim must be to ensure that these children are afforded the maximum chance of a healthy start in life. The direct link between the number of embryos transferred to the uterus during IVF treatment and the chance of twin pregnancy is beyond dispute. It is the view of the organizations contributing to this document that, with much of Europe now offering elective single embryo transfer (SET) as the norm, continued high multiple embryo transfer and twin pregnancy rates are impossible to justify. Measures to reduce the burden of twin pregnancies will need to take into account the many and complex influences on clinical and laboratory practice in the UK. This consensus statement brings together the views of providers of treatment (clinicians, scientists