Cervical collagen in non-pregnant women with previous cervical incompetence.

OBJECTIVE

To study the cervical collagen in non-pregnant women with a history of congenital cervical incompetence.

SUBJECTS

Ten non-pregnant women with congenital cervical incompetence, defined as cervical incompetence in the first pregnancy in a woman without previous cervical trauma. Seventy-one normal non-pregnant women (31 nulligravidae, nine nulliparous and 31 parous women) served as controls.

METHOD

Cervical biopsies were analysed for the hydroxyproline concentration and extractability to express the concentration and the stability of the collagen.

RESULTS

Women with cervical incompetence had markedly lower median cervical hydroxyproline concentration when compared to normal parous women (11.1 (range 6.11-18.5) micrograms/mg wet weight vs. 16.9 (range 7.7-29.8) micrograms/mg wet weight; P = 0.003, Mann Whitney test) and the extractability was almost twice the value found in normal parous women (80.2% vs. 49.5%; P = 0.03, Mann Whitney test). Both pregnancy per ce and parturition caused a significant decrease in the hydroxyproline concentration when compared to values found in nulligravidae (P < 0.0001, Kruskall Wallis test).

CONCLUSIONS

Congenital cervical incompetence seems associated with a low collagen concentration in the cervical connective tissue in the non-pregnant state.