Cervical collagen and hydroxy-prolin ratios physiologic changes of collagen during first trimester

Aim

The cervical tissue consists mainly of an extracellular matrix rich in collagen; important fort the biomechanical properties. During normal gestation, the biomechanical strength of the cervix is determined by the collagen concentration. This study demonstrates the differences and changes of cervical collagen in first trimester abortions and its relation with age and parity.

Methods

Cervical punch biopsies were obtained from 59 patients divided into two groups: first trimester abortion group (study group; n= 45), and patients with cervical biopsy due to gynecologic reasons (control group; n= 14). According to their gestational weeks, 45 first trimester pregnant women (median age=28.2) were divided into 3 groups (<7 weeks, 7-9 weeks, >9 weeks). Biochemical testing was performed and collagen quantity (as μg OH-prolin/mg dry weight) was determined. Hydroxyproline was measured in cervix tissue by the method of Switzer. Finally, the results of collagen and its relation with age and parity were investigated.

Results

Collagen quantity was lower in the first trimester pregnant women group (13.06 ± 4.17 µg OH-prolin/mg tissue) (p= 0.0001) compared with the control group (24.48±12.87). Moreover, when data were adjusted for gestational weeks, no difference in collagen quantity was found between <7 weeks and control groups (17,01 ± 1,11 µg OH-prolin/mg tissue) (p= 0,047). However the collagen quantities of 7-9 weeks (12.07±3.85 µg OH-prolin/mg tissue) and >9 weeks (11.16±4.39 µg OH-prolin/mg tissue) groups were statistically lower compared with the control group (p=0.0001). Furthermore, the results of first trimester pregnancy group were evaluated for age and parity. Lineer regression analyses shows that collagen increases with age and decreases with parity.

Conclusions 

Our study shows that, the collagen content of cervix started to decrease as early as first trimester of gestation. We observed that, from the beginning of 7th gestational week, cervical collagen starts to decrease. In accordance with the literature knowledge, collagen quantity increases with age and with regard to parity.

Keywords

Cervical collagen, first trimester physiologic changes