The effect of first trimester hemoglobin levels on pregnancy outcomes

OBJECTIVE: The relationship between hemoglobin levels and pregnancy outcomes is still a challenging issue. There is a supported opinion about the increased adverse pregnancy outcomes both with low and high hemoglobin levels. In this study, we aimed to evaluate this association for first trimester hemoglobin levels in a Turkish population. MATERIALS AND METHODS: In this retrospective study, 1306 women who were followed up during their pregnancy and gave birth in our clinic were enrolled. The patients were divided into three groups: hemoglobin <11 g/dL (n=490), 11≤ hemoglobin <13 g/dL (n=673), and hemoglobin ≥13 g/dL (n=143). The hemoglobin <11 g/dL group was classified into two subgroups as hemoglobin ≤9 g/dL (n=64) and hemoglobin >9 g/dL (n=426). Demographic characteristics, first trimester hemoglobin levels, gestational age at delivery and mode, birth weight, Apgar scores, and pregnancy outcomes were recorded and compared between the groups. RESULTS: Pregnancy-induced hypertension, preterm birth, neonatal intensive care unit admission, birth weight, gestational age at delivery, Apgar scores, and postpartum hemorrhage were significantly different between the three groups. In the pairwise comparison, gestational age at delivery, birth weight, and first minute Apgar scores were higher in the 11≤ hemoglobin <13 g/dL group, and pregnancy-induced hypertension was more common in the hemoglobin ≥13 g/dL group as compared with the others. Moreover, the preterm delivery rate was highest in the hemoglobin ≥13 g/dL (26.6%) group and lowest (7.3%) in the 11≤ hemoglobin <13 g/dL group. The neonatal intensive care unit admission rate was higher both the hemoglobin <11 g/dL and hemoglobin ≥13 g/dL groups. Postpartum hemorrhage was more common in the hemoglobin <11 g/dL group as compared with the other groups. Furthermore, pregnancy-induced hypertension was more common in the hemoglobin ≤9 g/dL subgroup (p=0.012). CONCLUSION: In conclusion, both low and high hemoglobin levels are related with adverse pregnancy outcomes. We suggest that hemoglobin levels must be screened during pregnancy to provide maternal and fetal well-being.