Table 3. Serum level changes of BTMs during the chemotherapy process.

	Control	C0	C1	C2	C3	C4	Pa	Pb
Premenopausal
E2 (pg/mL)	159.8±117	148.6±160	60.2±56	31.5±30	11.3±10	7.1±3.1	0.203	0.00*
FSH (IU/L)	5.65±3.7	12±2.1	33.6±42	42.5±41	66.1±37	79.8±32	0.856	0.00*
25(OH)D (nmol/L)	38.6±7	28.3±6	25.6±6	12.4±5	11.8±5	12.0±4.3	0.000†	0.00*
PTH (pg/mL)	40.3±14.8	34.8±11	33±11	36±15	32.64±11	31.6±11	0.172	0.381
Postmenopausal
E2 (pg/mL)	6.8±4.9	10.9±5	-	-	-	5.2±0.5	0.032*	0.01*
FSH (IU/L)	78.1±20	74.5±35	-	-	-	83.2±30	0.326	0.03*
25(OH)D (nmol/L)	39.1±5.2	32.8±11	25.6±12	29.3±10	26.8±8.6	27.1±13	0.051	0.02*
PTH (pg/mL)	42.8±14	37.4±15	36.5±15	40.3±15	41.4±13	38.8±15	0.248	0.346

Values were presented as mean± SD.

*Statistically significant at P < 0.05.

25(OH)D, 25-hydroxvitamin D; PTH, parathyroid hormone; E2, estradiol; FSH, follicle-stimulating hormone.

C₀, the day of initial diagnosis before chemotherapy;

C₁, 24 hours after the first cycle of chemotherapy;

C₂, 24 hours after the second cycle of chemotherapy;

C₃, 24 hours after the third cycle of chemotherapy;

C₄, 24 hours after the fourth cycle of chemotherapy.

P^a: comparison between the healthy control and the baseline of patients;

P^b: comparison between the baseline (C₀) and after the 4th cycle of chemotherapy (C₄).