The equivalent efficacy and superior safety of elective single embryo transfer (SET) compared with elective multiple embryo transfer (MET) after in vitro fertilization (IVF) has been established in recent medical literature. The transfer of a single high-quality embryo selected from a larger number of available embryos after IVF does not decrease implantation rates compared with MET and decreases the rate of twins from 30% to between 1% and 2%. 1 To reduce the complications associated with twin and higher-order multiple births-including medical and delivery complications for mothers, infant low birth weight, preterm birth, stillbirth, neonatal and infant mortality, and cerebral palsy 2 -practice guidelines have urged health care professionals to recommend SET in women younger than 35 years who have more than 1 top-quality embryo, who may have had a previous successful IVF cycle, and who are on a first or second treatment cycle. 3 There has been a resulting decrease in the proportion of transfers of 3 or more embryos from 70% to 39%. However, the United States has lagged behind the rest of the world in adoption of SET, with rates of twin pregnancy due to MET after IVF actually increasing in recent years. 4 Until recently, cost-effectiveness studies comparing elective SET with MET have focused on the easier-to-measure costs of achieving pregnancy and medical costs up to 4 to 6 weeks post partum, with conflicting results. 5-7 To our knowledge, longer-term examinations of the relative cost of MET to families, payers, and society, as well as studies that more directly elicit patient perspectives, are lacking.The study by Chambers et al 8 in this issue of JAMA Pediatrics attempts to fill this gap by assessing the contribution of assisted reproductive technology to the frequency, duration, and cost of hospitalization in singleton, twin, and higher-order multiple children up to 5 years of life in Western Australia. The authors were able to take advantage of a validated linkage system between a regional birth registry, a reproductive technology registry, death certificates, and an inpatient hospital admission database to perform one of the largest population assessments of costs attributable to SET vs MET to date. 8 The study's authors demonstrated that, compared with singletons, twins and higher-order multiple children were 3.4 and 9.6 times more likely to be stillborn, respectively, and 6.4 and 36.7 times more likely to die during the neonatal period, respectively. Twins and higher-order multiples were 18.7 and 525.1 more times likely to be preterm and small for gestational age, respectively. The average hospital cost of singleton, twin, and higher-order multiple children to 5 years was $2730, $8993, and $24 411, respectively, with cost differences concentrated to the first year of life. Fifteen percent of inpatient costs could have been avoided if twins and higher-order multiples conceived with assisted reproduction had been born as singletons.The study's greatest strength was that it achieved longterm follow-up of a l...