How low birthweight and gestational age contribute to increased inpatient costs for multiple births.

The dramatic rise in the number of multiple gestation births has led to concerns about heavy resource use by these newborns and the design of cost-effective interventions. This study uses medical records data to compare single and multiple births in terms of hospital charges by cost center, length of stay, neonatal intensive care unit (NICU) days, and discharge status. Potential mediators examined were gestational age and birthweight. These factors, respectively, accounted for 50% and 40% of the increase in total charges due to multiple gestation. The remaining "direct effect" was due primarily to longer hospital stays among twins and higher daily charges among higher-order multiples. Room and board charges were higher for multiples, while charges in other categories were actually lower, after controlling for birthweight and gestational age. Birthweight and gestational age accounted fully for the increased use of NICU services among multiples. These results show that while prevention of multiple gestation, where possible, is of paramount importance, strategies that decrease preterm delivery and/or increase birthweight should attenuate the adverse economic impact of multiple gestation pregnancies.