Cervical collagen: an important regulator of cervical function in term labor.

This study provides the first clear evidence of a close correlation between the biochemical composition of the cervix and the clinical course of delivery in terms of cervical dilatation. Cervical biopsy specimens were obtained from three groups of patients: Group A, ten women with favorable cervix and spontaneous labor; group B, 12 women with unfavorable cervix given 0.5 mg prostaglandin E2 in gel intracervically for cervical priming and induction of labor; and group C, five women with unfavorable cervix and spontaneous labor. Cervical dilatation time was significantly longer (18 hours) for women in group C compared with women in group A (6.7 hours) and in group B (5.0 hours; P less than .001). The total amount of cervical collagen was significantly higher in women in group C at 8.58 micrograms/mg compared with 6.7 micrograms/mg in women in group A and 5.47 micrograms/mg in prostaglandin E2-treated women in group B. The amount of nonextractable collagen also was significantly higher in women in group C, 23.6% compared with 11.3% in group A, and 12.4% in group B (P less than .01). The collagenolytic activity was significantly increased in cervical biopsy specimens from prostaglandin E2 gel-treated patients--520 U/100 mg wet weight compared with 380 U/100 mg wet weight in untreated patients in group A (P less than .05). From these results it is concluded that cervical collagen is an important regulator of cervical function in late pregnancy and term labor; that prostaglandin E2 is involved in cervical priming, initiation, and progress of term labor.(ABSTRACT TRUNCATED AT 250 WORDS)