Effects of some drugs on ripening of uterine cervix in nonpregnant castrated and pregnant rats.

Saito, Yoshiharu; Takahashi, Shuzo; Maki, Masahiro

doi:10.1620/tjem.133.205

Cited by 13 publications

(6 citation statements)

References 8 publications

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“…This is in contrast to a report by Saito et al (1981) who found that E produced histological changes in the cervix consistent with those found in cervical ripening; however, ovariectomised non-pregnant rats were used, and this may not reflect the complex changes that occur during pregnancy.…”

Section: Discussioncontrasting

confidence: 87%

The effects of oestradiol and relaxin on extensibility and collagen organisation of the pregnant rat cervix

Cheah

Ng²,

Johgalingam³

et al. 1995

Journal of Endocrinology

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The effects of exogenously introduced oestradiol-17 beta (E) and relaxin (RLX) on cervical extensibility and collagen organisation were tested in rats ovariectomised in late pregnancy. When the cervices were stretched in vitro by 1 mm increments, it was found that those from rats given E alone generated significantly higher tensions than those from control rats, while cervices from rats given both E and RLX had tensions similar to controls. Examination of cervical sections under the light microscope and ultra-thin sections under the electron microscope showed that the collagen fibres in the cervices from E-treated rats were highly organised, whereas those from animals given E+RLX and control animals were disorganised and dispersed. It was concluded that E decreased cervical extensibility, while RLX counteracted the effect of E to maintain a soft and easily extensible cervix.

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Section: Discussioncontrasting

confidence: 87%

The effects of oestradiol and relaxin on extensibility and collagen organisation of the pregnant rat cervix

Cheah

Ng²,

Johgalingam³

et al. 1995

Journal of Endocrinology

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“…Although the original focus of the effect of progesterone in pregnancy maintenance was on the myometrium54–63, it is now clear that this hormone exerts biological effects on the chorioamniotic membranes64–67 and the uterine cervix68–96. Indeed, progesterone is considered key in the control of cervical ripening70–78, 80–84, 86, 87, 89, 91, 92, 94–96. The precise mechanism by which progesterone prevents preterm delivery in women with a short cervix has not been established.…”

Section: Discussionmentioning

confidence: 99%

Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double‐blind, placebo‐controlled trial

Hassan¹,

Romero²,

Vidyadhari³

et al. 2011

Ultrasound in Obstet & Gyne

830

585

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Objectives Women with a sonographic short cervix in the mid-trimester are at increased risk for preterm delivery. This study was undertaken to determine the ef cacy and safety of using micronized vaginal progesterone gel to reduce the risk of preterm birth and associated neonatal complications in women with a sonographic short cervix. Methods This was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled asymptomatic women with a singleton pregnancy and a sonographic short cervix (10–20 mm) at 19 + 0to23 + 6 weeks of gestation. Women were allocated randomly to receive vaginal progesterone gel or placebo daily starting from 20 to 23 + 6 weeks until 36 + 6 weeks, rupture of membranes or delivery, whichever occurred rst. Randomization sequence was strati ed by center and history of a previous preterm birth. The primary endpoint was preterm birth before 33 weeks of gestation. Analysis was by intention to treat. Results Of 465 women randomized, seven were lost to follow-up and 458 (vaginal progesterone gel, n = 235; placebo, n = 223) were included in the analysis. Women allocated to receive vaginal progesterone had a lower rate of preterm birth before 33 weeks than did those allocated to placebo (8.9% (n = 21) vs 16.1% (n = 36); relative risk (RR), 0.55; 95% CI, 0.33–0.92; P = 0.02). The effect remained signi cant after adjustment for covariables (adjusted RR, 0.52; 95% CI, 0.31–0.91; P = 0.02). Vaginal progesterone was also associated with a signi cant reduction in the rate of preterm birth before 28 weeks(5.1%vs10.3%; RR, 0.50;95%CI, 0.25–0.97; P = 0.04) and 35 weeks (14.5% vs 23.3%; RR, 0.62; 95% CI, 0.42–0.92; P = 0.02), respiratory distress syndrome (3.0% vs 7.6%; RR, 0.39; 95% CI, 0.17–0.92; P = 0.03), any neonatal morbidity or mortality event (7.7% vs 13.5%; RR, 0.57; 95% CI, 0.33–0.99; P = 0.04) and birth weight < 1500 g (6.4% (15/234) vs 13.6% (30/220); RR, 0.47; 95% CI, 0.26–0.85; P = 0.01). There were no differences in the incidence of treatment-related adverse events between the groups. Conclusions The administration of vaginal progesterone gel to women with a sonographic short cervix in the mid-trimester is associated with a 45% reduction in the rate of preterm birth before 33 weeks of gestation and with improved neonatal outcome.

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“…Some studies show that estrogens (17b-esradiol) reduce cervical ripening in ovariectomized rats [6] while other studies indicate that they ripen the rat cervix [42]. There are also contradictory reports regarding the effect of estrogen on the cervical ripening induced by relaxin [5, 6].…”

Section: Discussionmentioning

confidence: 99%

Changes in cervical resistance and collagen fluorescence during gestation in rats

Shi

Saade³

et al. 1999

Journal of Perinatal Medicine

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During pregnancy the role of the cervix shifts between two opposing functions. Throughout most of gestation, the cervix is rigid and resists tension in order to maintain the products of conception inside the uterus. At term, however, cervical function changes drastically in order to accommodate stretch and delivery. The events that control cervical function are not known. The aim of this study was to characterize changes in cervical resistance and collagen content during pregnancy in the rat. To determine the change in cervical resistance, non-pregnant and timed pregnant Sprague Dawley rats were sacrificed at various times. Their cervices were isolated and suspended in organ baths connected to a cervimeter for measurement of the stretch-tension relationship. In a different group of animals, cervical collagen content was measured using light-induced fluorescence in non-pregnant and, longitudinally, in pregnant rats. Cervical resistance and collagen content decreased progressively during pregnancy. The changes in cervical resistance mirrored those in cervical collagen content and the nadir in both occurred about two days prior to the onset of labor. Our study suggests that cervical preparation for delivery does not occur acutely at the time of labor and that cervical collagen content determines cervical resistance.

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Effects of some drugs on ripening of uterine cervix in nonpregnant castrated and pregnant rats.

Cited by 13 publications

References 8 publications

The effects of oestradiol and relaxin on extensibility and collagen organisation of the pregnant rat cervix

The effects of oestradiol and relaxin on extensibility and collagen organisation of the pregnant rat cervix

Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double‐blind, placebo‐controlled trial

Changes in cervical resistance and collagen fluorescence during gestation in rats

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