Abstract
Prenatal care refers to accurate and consistent performance of the principles important to maintain healthy pregnancy outcomes and also for mother and child health. One of the new indices to assess the adequacy of care is Revised Graduated Index of Prenatal Care Utilization (R-GINDEX).The study aims to assess the relationship between quantitative prenatal care factors and preterm labor and low birth weight using R-GINDEX. This historical cohort study has been conducted on 420 mothers during the first two years after delivery in 2010. The adequacy of care was calculated by R-GINDEX. Based on this index, participants have been divided into three care groups including inadequate, adequate and intensive care groups. A significant relationship has been found between R-GINDEX and preterm birth and low birth weight (P<0.05). Thus the probability of premature labor in inadequate care group (RR=3.93) and low birth weight (RR= 2.53) was higher than that of the adequate and intensive care group. The results showed that the quantity of prenatal care is effective in reducing preterm birth and low birth weight.