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

Table 2

Analysis of the difference in BTM level at different stages of pregnancy.

	Normal group (n = 120)	First trimester (n = 120)	Second trimester (n = 120)	Third trimester (n = 120)
PINP (ng/ml)	53 (43, 62)	48 (40, 55)	39 (30, 51)^ab	58 (39, 96)^bc
N-MID (ng/ml)	13.4 (11.3, 15.7)	9.6 (7.7, 11.8)^a	7.7 (6.1, 10.1)^ab	10.6 (7.6, 13.0)^ac
β-CTX (pg/ml)	264 (193, 376)	236 (172, 297)	268 (178, 353)	343 (231, 498)^abc
β-CTX/PINP	5.3 (3.8, 7.0)	5.3 (3.6, 6.2)	7.1 (4.8, 8.9)^ab	6.5 (4.1, 8.0)^a
β-CTX/N-MID	19.6 (14.6, 25.4)	25.7 (17.8, 32.2)^a	35.5 (28.4, 43.8)^ab	35.9 (28.2, 41.9)^ab

^aCompared to the normal group,  < 0.05. ^bCompared to the first trimester,  < 0.05. ^cCompared to the second trimester,  < 0.05. Data are presented as median (25–75%; interquartile range). Statistics were calculated by the Kruskal–Wallis test. PINP, procollagen type I N-propeptide; N-MID, N-terminal osteocalcin; β-CTX, C-terminal telopeptide of type I collagen.