HFEA says twin births are at an all-time low

The proportion of multiple births following IVF has fallen dramatically to six percent, according to the Human Fertilisation and Embryology Authority (HFEA).

The number of multiple births has reached an all-time low in the UK. 'This is a major success for UK healthcare. Multiple births can be dangerous for both patients and unborn babies and can put an additional burden on the NHS,' explained Julia Chain, chair of the HFEA.

The new report from the HFEA, published last week, summarised data on multiple births following IVF between 2015 and 2019. Multiple births carry a higher risk of prematurity, which can result in long-term health issues such as cerebral palsy and learning difficulties in the child. Women carrying multiple pregnancies are also at a higher risk of pre-eclampsia and late miscarriage. The HFEA reported a substantial reduction in the UK multiple birth rate from the 1990s to 2019, falling from 28 percent to just six percent.

Importantly, the HFEA found that the reduction in multiple births by transferring only one embryo at a time does not seem to have had an impact on success rates. On the contrary, IVF success rates have steadily improved. In addition, no difference was found between IVF success rates for patients using the NHS and patients whose treatment was funded privately. However, the rate of multiple births was higher among young, privately funded patients (nine percent) compared to NHS patients (five percent).

Historically, multiple birth rates following IVF have been higher than multiple birth rates following natural conception, because of multiple embryos being transferred into the womb at once. The practice of triple embryo transfer was restricted in 2003 to patients under 40, apart from in exceptional circumstances. Then in 2007, the HFEA's 'One at a Time' campaign encouraged clinics to practise single embryo transfer and freeze other viable embryos. Single embryo transfers have since limited the rate of multiple births to between one and three percent across all age groups.

The HFEA's report did, however, reveal that multiple birth rates have not fallen evenly across all demographics. Multiple births and multiple embryo transfers were significantly higher in black patients than in other ethnic groups, at a rate of 12 percent compared with an average of ten percent across other groups. Consequently, black women and their babies remain at a higher risk from the complications of a multiple birth.

Chain affirmed that the HFEA will 'encourage clinics to review their multiple birth strategies, particularly in relation to patients from ethnic minority groups as we want to achieve a level playing field for all patients.'