Reducing multiple pregnancy in assisted reproduction technology: towards a policy of single blastocyst transfer in younger women.

OBJECTIVES

To investigate the effects of single blastocyst transfer (SBT) on live birth and multiple pregnancy in women undergoing in vitro fertilisation (IVF).

DESIGN

Descriptive cohort study.

SETTING

A London private IVF/postgraduate training unit.

SAMPLE: A total of 700 fresh and 102 frozen blastocyst cycles performed between January 2005 and December 2006.

METHODS

Young women aged 25-37 years and those aged 38-43 years were further divided into those who had SBT and those who received two blastocysts (double blastocyst transfer [DBT]). Live birth and multiple pregnancy rates were compared between groups. Cumulative live birth was compared between women who had DBT and those who received a SBT followed by a frozen blastocyst if the fresh cycle was unsuccessful.

MAIN OUTCOME MEASURES: Live birth rate, cumulative live birth rate, multiple pregnancy rate, uptake of SBT.

RESULTS

Among women aged 25-37 years, live birth rate following SBT was 59.0 versus 60.7% following DBT. The twin pregnancy rate in this group was 2.3 and 47.6% respectively. For women aged 38-43 years, live birth following SBT was 29.4% and multiple pregnancy rate was 33.3%. DBT in older women gave a higher live birth rate (44.3%) and a multiple pregnancy rate of 36.4%. Cumulative live birth following SBT in women aged 25-37 years was 72.8% versus 60.5% following DBT. Among the women aged 38-43 years, cumulative live birth was higher (63.3%) following DBT versus 28.6% following SBT.

CONCLUSION

Single blastocyst transfer followed by transfer of a frozen blastocyst if the preceding fresh cycle was unsuccessful resulted in a better cumulative live birth and lower twin pregnancy in young women. In older women, two fresh blastocysts gave better results than one fresh followed by a frozen cycle. Older women should have the option of replacing two fresh blastocysts as this optimises their chances of taking home a baby.