A universal standard of the birth weight for gestational age cannot be made since birth weight distribution varies with races, nations and eras. This report aims to establish the birth weight for gestational age patterns by sex, plurality, and parity, specific for Korean live births.

The national birth certificate data of all live births in Korea from January 2000 to December 2004 were used: for live births with gestational age 24 weeks to 42 weeks (n=2,585,5160), mean birth weight, standard deviation and 10th, 25th, 75th and 90th percentile values were obtained for each gestational age group by one week increment. To establish final standard values of Korean birth weight distribution by gestational age, the finite mixture model to eliminated erroneous birth weights was used for respective gestational age. Same as above method the birth weight for gestational age standard by sex, plurality, and parity were completed.

The male newborns are more heavier than female during the entire gestational age. The singletons are more heavier than twin during the entire gestational age. The para 2 are more heavier than the para 1 during the entire gestational age. Korean standard was more heavier in 10th and 50th percentile than Lubchenco's standard. Alexander's standard was more heavier in 50th and 90th percentile than Korean standard.

These birth weight for gestational age patterns by sex, plurality, and parity are similar to the other standards. I hope that for Korean infants, this curve will help clinicians in defining and managing the large for gestational age infants and also for infants with intrauterine growth retardation.