The level of hemoglobin in pregnant mothers, the cut-off point of hemoglobin and its relationship with preterm delivery and low birth weight

Anemia increases the risk of adverse pregnancy outcomes including preterm delivery and low birth weight. This study was performed with aim to determine the relationship between the severity of anemia with preterm delivery and low birth weight and the level of hemoglobin which causes these consequences.

This cross-sectional study was conducted in 2019-2020 on 737 pregnant women referred to Ayatollah Rouhani Hospital in Babol who underwent delivery. Demographic information, hemoglobin level of mothers, gestational age, type of delivery, weight, height, head circumference and Apgar of the newborn were recorded in the checklist. Data were analyzed by SPSS (version 25) and univariate ANOVA, t-test, Chi-square and correlation coefficient tests.

The prevalence of anemia in pregnant mothers was estimated at 24.15%. Gestational age, weight, height, head circumference, and Apgar of the newborn were significantly lower in the anemic group (p<0.001). By dividing the mothers into two groups of term and pre-term, there was no significant difference in their hemoglobin level (p=0.11); however, by dividing preterm mothers into early and late preterm groups, hemoglobin was reported to be lower in early preterm mothers (p=0.004). It was found that hemoglobin less than 11.7 g/dL in a pregnant mother increases the risk of preterm delivery (less than 34 weeks) and birth weight less than 2500 g.

It seems that despite reaching the hemoglobin to the minimum normal level, there is still a significant possibility of adverse outcomes in the newborn, so one should try to keep the hemoglobin level above the minimum normal level.