Anemia in pregnancy is a public health concern. It has been diagnosed in 27% of pregnant women in Malaysia and up to 40% of pregnant women globally. This study aimed to develop and evaluate the effectiveness of an intervention initiative based on the health belief model. The MyPinkMom program was disseminated through a mobile messaging application to pregnant women to educate them on the prevention of anemia in pregnancy. We conducted a two-arm cluster-assignment, single-blinded, randomized control trial at two government antenatal clinics in Selangor. One clinic was randomly chosen as the intervention group, and the other was chosen as the control group. Sixty pregnant women with anemia from the intervention group received the MyPinkMom intervention program in the form of six infographic video clips, and 60 pregnant women with anemia from the control group received routine counseling on anemia in pregnancy. Pregnant women who had anemia secondary to hemoglobinopathy or other chronic diseases were excluded from this study. MANOVA showed significant increases in hemoglobin, knowledge, attitude, subjective norms, and perceived behavioral control scores for adherence to iron supplements, dietary iron, and dietary vitamin C intake (p < 0.001) in the intervention group at week 6. A significant reduction also occurred in dietary tannin intake (p < 0.001) in the intervention group at week 6. The intervention group at week 6 showed a large effect on hemoglobin level increments (partial eta squared, Ƞp2 0.268), dietary iron intake (Ƞp2 0.213), knowledge of anemia in pregnancy (Ƞp2 0.622), subjective norm scores for adherence to iron supplements (Ƞp2 0.167), and reduction in dietary tannin intake (Ƞp2 0.353). Similarly, repeated measures ANOVA showed that changes in hemoglobin levels were significantly different over time (i.e., at baseline, week 6, and week 12) between the intervention and control groups (p < 0.001). Hemoglobin increased rapidly over time among participants in the intervention group but gradually in the control group. To conclude, the newly developed MyPinkMom program that was delivered through a messaging application showed effectiveness in preventing anemia during pregnancy.