Date of Delivery in Multifetal Pregnancies

To the Editor.  —The study reported by Drs Minakami and Sato¹ describing the optimal estimated date of delivery for multifetal pregnancies based on live born and stillborn infants of singleton and multiple pregnancies in Japan between 1989 and 1993 has limited applicability in the United States for several reasons. First, births to Asians or Pacific Islanders comprise less than 4% of total births in the United States.² Second, Asian infants, regardless of country of birth or socioeconomic status, have similar birth-weight distributions, whereas Asian infants and white infants (78% of US births), even of the same socioeconomic background, have different birth-weight distributions.³ Third, by grouping all infants of multiple births together, the authors have blurred the vastly greater risks experienced by infants of triplet and higher-order births. The optimal birth weight and gestational age associated with the lowest risk of morbidity and mortality for infants of multiple