Background and Objectives: Women are more prone to iron deficiency (ID) anemia when pregnant. The diagnostic use of mean reticulocyte volume (MRV) in identifying ID anemia during pregnancy has not been thoroughly investigated. The objective of this study is to evaluate the effectiveness of MRV in diagnosing ID in pregnant women., Methods and Study Design: Firstly, MRV of 20 healthy female volunteers (healthy group) was measured on specific days for one month. Subsequently, clinical data from 724 pregnant women were thoroughly examined. These women were divided into two groups: 282 with ID (research group) and 442 without ID (control group). Parameters such as MRV, reticulocyte hemoglobin equivalent (RHE), red blood cell volume distribution width-standard deviation (RDW-SD), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hematocrit (HCT), reticulocyte count (RET), MRV/MCV ratio, and serum ferritin (SF) were analyzed and compared., Results: MRV remained consistent over a period of one month for 20 healthy individuals. In addition, there were significant differences in MRV, RHE, RDW-SD, MCV, MCH, MCHC, HCT, RET, and MRV/MCV between the research group and control group. The receiver operating characteristic (ROC) analysis showed that the areas under the curve (AUCs) for these measures were as follow: 0.840, 0.837, 0.676, 0.654, 0.639, 0.602, 0.571, 0.550, and 0.816, respectively. Ultimately, there was a substantial disparity in MRV prior to and following therapy with oral iron treatments., Conclusions: In healthy women, MRV remains stable and is a reliable ID marker, which can be used to assess oral iron treatment effectiveness during pregnancy., Competing Interests: The authors declare no conflict of interest