Objectives: To assess calcium status in healthy pregnant women during limited sun exposure time in winter, and to demonstrate the possible effect of serum albumin alterations on serum total calcium level and the role of albumin adjusted calcium concentration. Methods: Subjects enrolled in the study included 160 apparently healthy women divided equally into four groups (I - IV), group I was considered as the control group, composed of non-pregnant women. Groups II-IV were composed of pregnant women in the first, second and third trimesters respectively. Semiquantitative urine protein determination and measurement of serum total calcium, ionized calcium, albumin, phosphorous and creatinine with calculation of corrected calcium were performed in all groups. The results were statistically evaluated by standard statistical methods. Results: There was no significant difference in serum ionized calcium, corrected calcium and phosphorous during pregnancy. However, there was a significant reduction of serum total calcium, albumin and creatinine in pregnant women at second and third trimesters. In each group, a significant positive correlation was observed between total calcium with corrected and ionized calcium. Conclusion: In healthy pregnant women even during limited sun exposure time in winter, there was no need for calcium supplementation in spite of the continuous and progressive reduction of serum measured total calcium during the second and third trimesters due to dilutional hypoalbuminemia. During pregnancy, measured calcium is parallel to both corrected and ionized calcium and since there was no significant difference between measured and corrected calcium, therefore, measured calcium is a useful test in assessing calcium status and suggests the need to establish a reference range for pregnant women.