Cervical collagen is reduced in non‐pregnant women with a history of cervical insufficiency and a short cervix

TLDR

Preterm cervical shortening and cervical insufficiency may arise from inherent cervical weakness. This study evaluated cervical collagen concentrations in non‑pregnant women with a history of cervical insufficiency or a short second‑trimester cervix. Ectocervical biopsies from 55 controls, 27 insufficiency, 10 short‑cervix, and 10 long‑cervix women were analyzed for hydroxyproline to quantify collagen. Women with cervical insufficiency or a short second‑trimester cervix had markedly lower collagen (≈63–62%) than controls (≈68%), and a 67.6% cut‑off yielded 60% sensitivity and 81% specificity, demonstrating persistent collagen deficiency more than a year after pregnancy.

Abstract

INTRODUCTION: Preterm cervical shortening and cervical insufficiency may be caused by a constitutional weakness of the cervix. The aim of this study was to assess the cervical collagen concentration in non-pregnant women with a history of cervical insufficiency or of a short cervix in the second trimester of pregnancy. MATERIAL AND METHODS: In this case-control study we included non-pregnant women one year or more after pregnancy: 55 controls with a history of normal delivery; 27 women with a history of cervical insufficiency; and 10 women with a history of a short cervix (<5th percentile) and 10 women with a history of a long cervix (>95th percentile) at gestational weeks 18-20. We obtained biopsies (3 × 3-4 mm) from the ectocervix and determined the collagen concentration by measuring the hydroxyproline concentration. RESULTS: Women with cervical insufficiency had lower collagen concentrations (63.5 ± 5.1%; mean ± SD) compared with controls (68.2 ± 5.4%; p = 0.0004); area under the ROC curve 0.73 (95% CI 0.62-0.84). A cut-off value at 67.6% collagen resulted in a positive likelihood ratio of 3.2, a sensitivity of 60%, and a specificity of 81%. Also, women with a short cervix in the second trimester had lower collagen concentrations in a non-pregnant state (62.1% ± 4.9%) compared with women with a long cervix (67.8% ± 5.0%; p = 0.02). CONCLUSIONS: Both cervical insufficiency and a short cervix in the second trimester of pregnancy are associated with low cervical collagen concentrations in a non-pregnant state more than one year after pregnancy.