Changes in Serum Concentrations of Bone Turnover Markers in Healthy Pregnant Women

Table 1

The general characteristics and biochemical indices of subjects.

	Normal group (n = 120)	First trimester (n = 120)	Second trimester (n = 120)	Third trimester (n = 120)
Age (years)	27.5 ± 3.7	28.2 ± 2.6	28.3 ± 2.4	28.4 ± 2.4
BMI (kg/m^2)	20.3 ± 2.8	22.0 ± 2.5	23.8 ± 2.3	25.7 ± 2.5
Gestational weeks	—	8.9 ± 1.5	20.1 ± 2.9	33.0 ± 3.1
25(OH)D (ng/ml)	15.7 (11.8, 23.1)	18.4 (11.3, 23.4)	23.3 (14.0, 31.8)^a	31.6 (25.7, 39.5)^ab
Ca (mmol/L)	2.40 (2.34, 2.45)	2.24 (2.20, 2.31)	2.19 (2.12, 2.27)^a	2.19 (2.13, 2.24)^a
Pi (mmol/l)	1.17 (1.07, 1.28)	1.18 (1.16, 1.31)	1.24 (1.13, 1.34)	1.29 (1.17, 1.37)^a
ALP (U/l)	63 (52, 75)	46 (35, 60)	60 (52, 82)^a	97 (85, 122)^ab

^aCompared to the first trimester,  < 0.05. ^bCompared to the second trimester,  < 0.05. Data are presented as mean ± standard deviation or median (25–75%; interquartile range). Statistics were calculated by the paired t-test. BMI, body mass index; Ca, calcium; Pi, phosphorus; ALP, alkaline phosphatase.