Background: Anemia during pregnancy is a significant public health issue, especially among tribal populations in India, due to poor nutrition, limited healthcare access, and a high prevalence of hemoglobinopathies. Morphological classification aids in understanding etiology and guiding interventions. Objective: To assess morphological patterns of anemia among tribal pregnant women in Ranchi, Jharkhand, across trimesters. Methods: A cross-sectional study was conducted on 406 anemic tribal pregnant women attending the Obstetrics and Gynaecology Department at a tertiary care centre in Ranchi, Jharkhand (January–December 2017). Hemoglobin estimation, peripheral smear examination, and sickle cell screening were performed. Anemia was classified as mild (10.0–10.9 g/dl), moderate (7.0–9.9 g/dl), and severe (<7.0 g/dl). Trimester-wise distribution of morphological anemia types was analyzed using chi-square tests, followed by pairwise Fisher’s exact tests with Bonferroni correction. Results: Microcytic hypochromic anemia was most common (51.0%), followed by dimorphic (26.8%), normocytic normochromic (11.6%), macrocytic (6.2%), sickle cell anemia (4.2%), and pancytopenia (0.2%). Most women had mild (52.0%), moderate (39.2%), and severe (8.8%) anemia. Significant differences in anemia distribution were observed across trimesters (p < 0.001). Microcytic anemia predominated in all trimesters, with dimorphic anemia more common in later trimesters. Conclusion: Microcytic hypochromic anemia predominates among tribal pregnant women in Ranchi, with dimorphic anemia also prevalent. The findings indicate combined iron, folate, and vitamin B12 deficiencies, alongside hemoglobinopathies, emphasizing the need for early screening, nutritional interventions, and routine sickle cell testing in antenatal programs for tribal populations.