Epidemiology of pregnancies with unknown last menstrual period

Abstract

the Epidemiology of normal pregnancies with unknown last menstrual period (LMP) was studied in 1192 singleton pregnancies.the LMP was unknown in 240(20.3%) pregnancies.unknown LMP is associated with high rates of low birth weight and all low socio-economic and socio-demographic status.such characteristics are also associated with a high rate of preterm deliveries.any possible bias introduced in studies prematurity by ignoring the group of women with unknown LMP should be carefully checked.