Table1.
Cervical tissue tensile tangent moduli from uni-axial ex vivo mechanical tests. The strain level reported is location of the tangent moduli. PG=pregnant, NP=nonpregnant, ex.=external, int.=internal, circ=circumferential, long.=longitudinal, PGE2=Prostaglandin E2, CI=cervical insufficiency, instan=instantaneous, eq=equilibrium.
| Reference | Specimen description | Strain rate strain level | Tangent modulus (MPa) |
|---|---|---|---|
| Conrad and Ueland, 1976 | NP and PG Term | Rate: 0.22 %/s | NP: 0.055 |
| ex. os biopsy (5 × 10 mm) | Level: 0.8 | PG: 0.021 | |
| Conrad and Ueland (1979) | PG Term Non-treated | Rate: 0.22 %/s | PG: 0.027 |
| PG Term Oxytocin- & PGE2-treated | PG Oxytocin: 0.029 | ||
| ex. os biopsy | PG PGE2 0.015 | ||
| Conrad et al. (1980) | NP int. os | Not given | NP inner: 0.0643 |
| rectangular circ. strips | NP middle: 0.0413 | ||
| in 3 radial zones | NP outer: 0.0242 | ||
| Rechberger et al. (1988) | NP and PG at post partum | Rate: 1.11 %/s | NP inner: 40.3 |
| ex. os biopsy (2 × 2 × 12 mm) | Level NP: 0.61 | PG: 1.84 | |
| Level PG: 0.93 | |||
| Petersen et al. (1991) | NP int. and ex. os | Rate: 5.55 %/s | NP int os circum: 4 |
| biopsy taken in | Strain: level: 0.7 | NP int os long: 3.9 | |
| circ. and long. directions | NP ex. os circum: 3.6 | ||
| (1–2 × 10 mm) | NP ex. os long: 3.2 | ||
| Oxlund et al. (2010a,b) | NP with and w/out history of CI | Rate: 4.17 %/s | NP no history: 5.33 |
| ex. os biopsy | Level: 0.49 | NP w/ history of CI: 5.41 | |
| taken in long. direction (2 × 15 mm) | |||
| Myers et al. (2010) | NP and PG Term | Rate: 0.1 %/s | NP instan: 0.837 eq. 0.554 |
| rectangular circ. strips (2 × 4 × 10 mm) | Level NP: 0.25 | PG instan: 0.003 eq. 0.003 | |
| Level PG: 0.35 |