Christina Bergh, M.D., Ph.D., Mohan S. Kamath, M.S., D.N.B., Rui Wang, M.D., Ph.D., Sarah Lensen, Ph.D.
Multiple birth rates after fertility treatment are still high in many countries. Multiple births are associated with increased rates of preterm birth and low birth weight babies, in turn increasing the risk of severe morbidity for the children. The multiple birth rates vary in different countries between 2% and 3% and up to 30% in some settings. Elective single-embryo transfer, particularly in combination with frozen-embryo transfer and milder stimulation in ovulation induction/intrauterine insemination, to avoid multifollicular development is an effective strategy to decrease the multiple birth rates while still achieving acceptable live-birth rates. Although this procedure is used successfully in many countries, it ought to be implemented broadly to improve the health of the children. One at a time should be the normal routine.