Research on the correlation and regulation of bone metabolism related biochemical indexes in different gestational ages

Objective To investigate the correlation and metabolic characteristics of the growth hormone (GH) and other bone metabolism related biochemical markers in pregnancy women serum. Methods Determination of GH, 25 hydroxy vitamin D(25(OH)D), osteocalcin n-terminal fragments (N-MID), total propeptide of type 1 procollagen (TP1NP) and alkaline phosphatase (ALP) levels in different gestation women serum, the experimental group involving 75 cases of early pregnancy women(11-14 weeks), 135 cases of pregnancy women(15-21 weeks), 62 cases of late pregnancy women(31-40 weeks) and 28 cases of postpartum women(1-3 days). All cases were selected from prenatal screening patients in hospital from February 2016 to February 2017. The control group involving 55 cases of physically healthy nulliparous. The indicators of GH, 25(OH)D, TPINP and N-MID were detected by electrochemiluminescence and ALP were detected by rate method. All data were processed by SPSS. Variance analysis and Pearson correlation analysis were employed. Results Serum GH level in early pregnancy, pregnancy, late pregnancy and control group were (4.54±2.26), (9.04±3.23), (20.16±4.89), (0.55±0.49)μg/L, respectively. The difference was statistically significant (F=270.037, P<0.01). Serum GH in each group of pregnant women were more higher than those in control group (all P<0.01), and there was statistical difference in different gestational stages(all P<0.01). Serum 25 (OH)D expression in early pregnancy, pregnancy and late pregnancy were (25.60±14.48), (27.10±12.05), (25.45±9.85)nmol/L. Compared with the control group(39.93±14.88)nmol/L, the difference was statistically significant (all P<0.01). Serum TP1NP level in early pregnancy, pregnancy, late pregnancy and control group were (44.44±11.80), (48.41±20.87), (102.63±41.73), (54.73±24.07)μg/L, respectively. The difference was significantly significant (F=54.027, P<0.01) and TP1NP in late pregnancy group was obvious higher than in early pregnancy group, pregnancy group and control group apart(all P<0.01). Serum N-MID level in early pregnancy, pregnancy, late pregnancy and control group were (5.91±2.64), (7.45±2.27), (17.24±6.47), (18.52±6.95)μg/L, and the difference was significantly significant(F=55.699, P<0.01). N-MID in early and middle pregnancy group were apparent lower than that in late pregnancy and control group (all P<0.01). Serum ALP level in early pregnancy, pregnancy, late pregnancy and control group were (49.74±10.14), (77.76±26.90), (168.34±45.15), (52.81±10.33) U/L, and the difference was significantly significant(F=180.349, P<0.01). However, there was noticeable difference in ALP level between late pregnancy and other pregnant group(P<0.01 or P<0.05). The serum GH, TP1NP and N-MID in postpartum women (1-3 days) were (1.44±0.99), (73.41±34.27), (12.10±5.64) μg/L, respectively. Compare with late pregnancy groups, the difference was significantly significant(all P<0.01). The content of GH in serum of 272 cases pregnant women was positively correlated with the concentration of TP1NP, N-MID and ALP, the gestational age and body weight of pregnant women(r=0.509, 0.720, 0.862, 0.827, 0.324, all P<0.01). The content of TP1NP, N-MID and ALP were positively correlated with gestational age, respectively(r=0.603, 0.722, 0.901, all P<0.01). Moreover, TP1NP expression was positively correlated with N-MID (r=0.849, P<0.01), and there was no correlation between other indexes. Conclusions These findings have revealed that there are different metabolic character of the GH and bone metabolism related biochemical indexes during different pregnancy period. And there is a positive correlation between gestational age and the index of GH, N-MID, TP1NP, ALP, respectively. Finally, the bone metabolism is more active and Vitamin D deficiency is severe throughout pregnancy. Key words: Pregnant women; Metabolism; Growth hormone; Vitamin D