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Consultations & reviews of policy

Multiple births and single embryo transfer review


The single biggest risk of fertility treatment is multiple pregnancy. It increases the risk of stillbirth, neonatal death and disability in children born. It also increases the risk of dangerous complications to the mother, such as late miscarriage, high blood pressure and pre-eclampsia.

On average, one in five IVF pregnancies are a multiple pregnancy compared to one in 80 for women who conceive naturally.  With approximately 13,000 IVF babies being born each year this contributes significantly and disproportionately to the national multiple birth rate and presents a significant public health concern. 

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Consultation process

In 2005, the HFEA commissioned a group of fertility and public health experts to report on the risks of multiple births from fertility treatment.

The Expert Group published the 'One child at a time' report in October 2006. They concluded that the risk of multiple births could be minimised, whilst maintaining patients’ overall chance of becoming pregnant, by transferring one embryo to IVF patients who have the highest chance of conceiving and therefore are at the highest risk of conceiving twins. This is known as elective single embryo transfer (eSET).

Following this report, we launched a public consultation in 2007 on the most suitable policy to reduce multiple births and promote eSET in appropriate patients. We ran an online consultation alongside a wide range of stakeholder events for clinic staff, patients and professional groups.

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Consultation outcome

In October and November 2007, after careful evaluation of the consultation responses, the Authority made a decision to adopt an outcome-based policy, which allows centres the flexibility to develop their own eSET strategy that is appropriate for them and the patients they treat.

Key elements of the policy:

  • Overall aim to reduce the UK IVF multiple birth rate to 10% in stages over a period of years. 
  • The HFEA will set a maximum multiple birth rate that clinics should not exceed, which will be lowered each year.
  • All centres will devise their own ‘multiple births minimisation strategy’ setting out how they will not exceed the maximum multiple birth rate.
  • The HFEA policy will form part of a wider national strategy to reduce the risk of multiple births from fertility treatment involving professional bodies, patient groups and NHS-funding bodies.

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Year 1 of the multiple births policy

The policy was introduced in January 2009. The Authority set the Year 1 maximum multiple birth rate at 24% (the national average at the time). This means that no more than 24% of a centre’s annual live birth rate should be multiple births.

All centres are required to have a strategy in place stating how they would identify patients who should have elective single embryo transfer in order to reduce the centre’s multiple birth rate.

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Year 2 of the multiple births policy

In December 2009 we evaluated the first year of the multiple births policy, by analysing the available 2009 pregnancy data along with feedback from patients and clinics.

On the basis of this, in January 2010 the Authority set 20% as the Year 2 maximum multiple birth rate. The Authority decided that 20% would maintain the momentum that centres built up in 2009, whilst allowing centres time to review and improve their strategies to lower their multiple rate further. 

The Year 2 maximum multiple birth rate came into force on 6 April 2010, and means that no more than 20% of a centre’s annual live birth rate from treatment started from this date should be multiples.

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Year 3 of the multiple births policy

At the end of 2010 we evaluated the full Year 1 of the multiple births policy and the first six months of Year 2. We looked at the progress of individual centres and the sector as a whole in reducing multiples, and the impact on overall pregnancy rates.

On the basis of this in December 2010, the Authority set 15% as the Year 3 maximum multiple birth rate. Professional bodies and patient groups recommended 15% as a stretching but feasible target for centres to achieve that will help maintain the good progress centres have made so far.

The Year 3 maximum multiple birth rate of 15% came into effect in April 2011 and applies to all IVF births from treatments started between April 2011 and March 2012. In October 2011 the Authority also introduced guidance around double blastocyst transfer and a licence condition to strengthen the multiple births policy. 

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Year 4 of the multiple births policy

At the end of 2011 we evaluated the full Year 2 of the multiple births policy and the first seven months of Year 3.

On the basis of this, in January 2012, the Authority set the final (Year 4) maximum multiple birth rate at 10%, to come into effect on 1 October 2012.  This is the rate we have been aiming for from the outset of the policy. Ordinarily, the Authority introduces a new target rate each year in April. However, the Year 3 target has been challenging; so when making the decision about the Year 4 target the Authority acknowledged that centres need time to refine their strategies and implement changes.

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Sector performance so far

The sector as a whole has responded very well to the drive to reduce multiple births.

Since the introduction of the policy in January 2009, the proportion of eSET has increased, the multiple pregnancy rate has decreased and the overall pregnancy rate has remained steady.

The pregnancy rates from elective single embryo transfer are similar to the pregnancy rates from double embryo transfer. The national average data shows the sector as a whole was under the Year 1 (24%) and Year two (20%) maximum multiple birth rates and is predicted to be close to the Year 3 maximum multiple birth rate of 15%.

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Monitoring and enforcing the policy

We are committed to supporting centres implement the policy and to help share best practice across the sector. We are continually monitoring clinics’ performance and the impact of the policy on multiple and overall pregnancy and birth rates.

The Authority removed the licence condition T123 (which was introduced in 2011) from all centres’ licences, effective from 1 January 2014.

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How the HFEA has assessed centres' performance with the multiple births policy

We use Cumulative Sum Analysis (CUSUM) to monitor multiple clinical pregnancy rates in real time.

CUSUM plots have an upper threshold and when this threshold is breached it suggests that if the  centre’s multiple clinical pregnancy rate  continues at the same rate then they  would be unlikely to meet the target at the end of the year. If the centre reviews their strategy when the threshold is breached then it might still be possible to meet the target.

We will aim to support centres in meeting  the target by alerting them if trend analysis of  the multiple clinical pregnancy rate suggests they may not met the target. To support centres in their  efforts to meet the target while maintaining pregnancy rates centres have been able to access this CUSUM analysis directly, through the clinic portal, since February 2012.

Where centres continue to struggle to implement a strategy likely to keep them on target then we may invite the PR to a management review meeting to discuss options. 

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Further information

The HFEA policy works alongside the Multiple Births Stakeholder Group as part of a co-ordinated national strategy to reduce the risk of multiple births from fertility treatment. The stakeholder group represents professional bodies, patient organisations and NHS-funding bodies and works to:

  • share best practice and develop professional body guidance around eSET
  • provide information to patients and professionals about multiple births and eSET
  • advance NHS provision of fertility treatment

If you have further questions about the HFEA multiple births policy, contact:

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Supporting Documents

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Page last updated: 20 December 2013

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