Multiple births: An update

In vitro fertilization is now seen as a routine treatment to overcome infertility. While the success of IVF has improved dramatically over the years, this has been marred by a high multiple birth rate (MBR). When the HFEA commissioned an expert working party in 2005 to examine the impact of multiple births, the evidence was clear that multiple births were the single highest risk to the health and welfare of children born after IVF (Braude, 2006). Although the number of triplets in the UK had decreased following the introduction of a two embryo replacement policy in 2001, (HFEA Chairs letter 01(10)), the twinning rate remained unacceptably high. It was time for a change of practice and for multidisciplinary teams of clinicians, embryologists, nurses and counsellors to take on this challenge. Other countries such as Belgium, Australia and Sweden had shown that low multiple rates could be achieved by elective single embryo transfer (eSET) in those women most at risk.

The national ‘One at a Time’ strategy was established in 2007 with representation from professional bodies, patient groups and NHS funding bodies. A consensus statement was signed and published in 2009 showing a firm commitment to reducing the MBR (Hamilton, 2007). Workshops were organized around the UK and the group encouraged the sharing of best practice between Centres. Whilst the HFEA set the policy targets, the joint BFS/ACE guidelines published in 2008 provided guidance to Centres on how their clinical practice could change to meet these targets (Cutting et al., 2008). The targets were introduced in a stepwise fashion with the ultimate aim of reducing the MBR to 10%. The stakeholder group continues to maintain the website www.oneatatime.org.uk, that provides information and support for patients and professionals.

In response to new targets and an encouraging response from the sector, the consensus statement was updated in 2011 to reaffirm the commitment of the stakeholder organization to implementation of the policy. The revised statement reflects the increase in the rate of eSET and the small but downward trend in the number of multiple births evident in the latest statistical report released by the HFEA, Improving outcomes for fertility patients: Multiple Births 2011 (HFEA, 2011). In this report, the most dramatic change was the decrease in multiple deliveries seen in women aged 18–34 (31.2%–23.9%) although the overall drop was smaller (24% in 2008 to 22% in the first 6 months of 2009). It was also encouraging that in the first 6 months of 2010 the percentage of eSETs was 14.7% an increase of nearly 10% overall. Furthermore, in high risk patients, whilst the MBR fell overall, the pregnancy rate was maintained.

The increased use of blastocyst transfer has had an unpredicted effect on IVF outcome. From January 2010 to June 2010, 27.6% of all cycles had a blastocyst stage embryo transfer, a significant increase on previous years. However, the data show that replacing two blastocysts results in an unacceptable twin rate, with a multiple pregnancy rate of 44% in women under the age of 35, and 39.4% for patients aged between 35–37, the age range where only a small decrease in the overall MBR rate was observed (23.5%–22%). Practice is now changing and clinics are reviewing their criteria and policies for blastocyst transfer.

The 2011 consensus statement highlights where practice has changed for the better and where further improvements can be made to reach the target of a 10% MBR. Best practice for commissioners is an important component of the One at a Time strategy. It is essential that eSET is individualized for patients. Blanket policies which demand eSET for every patient have to be revised since the evidence indicates that eSET is not appropriate for every patient. Prognostic factors such as female age and embryo quality should be taken into account for each patient so that achieving a successful outcome is not compromised. The combination of fresh and frozen embryo transfer remains key to a successful eSET programme. Centres have embraced this approach and introduced strategies and new technology such as embryo vitrification to maximize patients’ chance of success. Fine tuning of cryopreservation and thawing/warming techniques should lead to further improvements in live birth rates after frozen embryo transfer.

Education is crucial for all parties so that the benefits of eSET as well as the risks of multiple pregnancies can be conveyed to patients. The inevitable and understandable concerns of patients that eSET could compromise their chances of a pregnancy and increase costs are well-recognized and need to be addressed. Likewise commissioners have to be made aware that the success of this initiative and the goals we are working towards will only be realized fully when consistent and equitable NHS funding is in place. There is irrefutable evidence that reducing iatrogenic multiple pregnancies will result in health service savings by reducing the costs of neonatal care (Lukassen et al., 2004). It is therefore essential that we continue to highlight the need to fund fresh and frozen cycles with full implementation within the NICE guidelines.

The UK must follow the example of countries such as Sweden in protecting the health of babies born after IVF treatment. In 2002, Swedish law changed to permit only one embryo to be replaced unless the perceived risks of twins would be very low. The eSET rate in 2004 was close to reaching 70% and the impact of this change in practice is reflected in a significant fall in the number of multiple pregnancies alongside a reduction in both neonatal and maternal complications (Kallen et al., 2010). Although progress has been made in the UK, multiple pregnancy rates are still over 20%, which indicate that meeting this year’s target of 15% and the future goal of 10% remains as a significant challenge.