Poorer quality second embryo can hamper IVF pregnancy chances

Putting two embryos back during IVF can cut the chance of falling pregnant by more than a quarter if one is poor quality, new research suggests.

A study of almost 1,500 embryos that were implanted in women of all ages found that putting back a good embryo with one that was poorer quality dramatically cut the chance of a successful pregnancy compared to just transferring one embryo.

Experts behind the study believe that the body tends to focus on the poorer quality embryo and rejects a possible pregnancy, rather than focusing on the healthy embryo that would lead to a successful birth.

The research, being presented at the British Fertility Society annual conference in Edinburgh, involved data for 1,472 fresh single and double embryo transfers on day five after fertilisation (blastocyst stage).

The transfers were carried out between June 2009 and December 2013 at the Nurture Fertility clinic in Nottingham.

Embryos were graded by an embryologist at the time of embryo transfer using a standardised grading system in IVF.

The results showed that compared to transferring a single embryo, transferring two embryos where one was good quality and one was poor resulted in a 27 per cent...