A distinct and linear reduction in multiple birth rates was observed along with little to no effect on clinic-level live birth rates with increasing rates of elective single embryo transfer (eSET) in women <38 years of age. This according to a cohort study of women aged <35 years and 35 to 37 years in US fertility clinics. Clinics were divided into groups based on eSET rates for each age group and aggregate rates of live birth per ET and multiple births per delivery were calculated. Researchers found:

• For each age group, there was a linear decrease in multiple birth rate with increasing eSET rate and no significant difference in clinic-level birth rates.

• In cycle-level analysis, there were slightly higher live birth rates with double ET, but it was mainly observed in women aged 35 to 37 years or with ≥4 embryos available for transfer.

• This confirmed the reduction in multiple births with eSET.

The authors concluded that eSET is effective in decreasing the high multiple birth rates associated with IVF and suggest that eSET be used more frequently than is currently practiced.