Table 2. Scores of premenstrual syndrome before and after the intervention in the two groups.

	Calcium group (n=32)	Placebo group (n=32)	P-value
Before the intervention (cycle 0)	10.59 (2.74)	8.41 (1.70)	0.741
After the intervention (cycle 1)	7.66 (3.05)	7.44 (2.10)	0.012
After the intervention (cycle 2)	5.56 (2.98)	8.28 (1.80)	0.001
P-value	0.01	0.2	-