The difference is small, but must be taken into consideration if comparing data directly between the two birthweight variables.
Only one study compared two birthweight standards in the same population.
Lower mean BPs were observed in participants belonging to the first three birthweight categories, while a higher mean BP was observed in the >3.5 kg group (table 1).
Likewise, perhaps more than two or three birthweight-specific mortality curves are needed to describe heterogeneity in mortality.
Among these completed pregnancies were: nine preterm births (23.7%), four abortions (10.5%, spontaneous and induced), four low birthweight term infants (10.5%), and one infant death.
10 With an average prevalence of low birth weight of 5.9%, an estimated 1.2 million low birthweight babies are born in China every year.
We therefore analysed observational data collected for a large prospective cohort study, the Caffeine and Reproductive Health CAREE) birth cohort in Leeds, UK, to examine the relationship between supplement use during the first, second and third trimesters of pregnancy and two outcomes: birthweight and preterm delivery.
Top Human Development Economist and Nobel Prize Winner James Heckman, in a New York Times report, refers to cognitive tests that began in the '80s with several hundred low-birthweight 3-year-olds who were retested periodically until the age of 18.
About 24 million low-birthweight babies are born every year, most of them in developing countries.
A comprehensive literature search found 15 relevant studies, most of which evaluated more than one outcome (four studies for preterm delivery, nine studies for gestational age, and ten studies for birthweight).
