Dynamics of Cervical Remodeling during Pregnancy and Parturition: Mechanisms and Current Concepts
ABSTRACT The cervix serves as a protective barrier from invading microorganisms and as a structural barrier to delivery of the fetus. Among all biological processes, the phenomenal connective tissue remodeling that occurs in the cervix during and after parturition is unparalleled in scope and magnitude. The process of connective tissue remodeling in the cervix during pregnancy occurs in four stages: softening, ripening, dilation, and repair. Although overlapping in time, each stage is uniquely regulated. Results from studies using serial measurements of cervical length indicate that cervical ripening precedes myometrial contractions of labor by several weeks, suggesting that parturition in women is a process of long duration and that uterine contractions of labor are late events in the parturition process. A clear understanding of the biologic mechanisms that regulate cervical remodeling during pregnancy is needed to influence the preterm birth rate and to develop strategies to prevent preterm dilation of the cervix.
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ABSTRACT: Objective: To describe the use of cervical inversion for postpartum hemorrhage (PPH) management during cesarean delivery for placenta previa accreta/increta. Methods: In a retrospective, descriptive study, data were reviewed for cases in which cervical inversion was used to manage PPH during cesarean delivery at a center in Zahedan, Iran, between July 2, 2011, and September 25, 2014. Cervical inversion was applied when placental bleeding was persistent and the sites could not be clearly located. The cervix is inverted using ring forceps or straight Allis forceps, after which the placental bed is sutured to control bleeding. After bleeding is controlled, the cervix is returned to its original position. Results: Cervical inversion was successfully applied to 10 cases. Mean time to completion of cervical inversion was 4.1 +/- 0.7 minutes. In all 10 cases, the bleeding was stopped within 3-5 minutes from the beginning of the cervical inversion procedure. No apparent complications were reported, and blood transfusions or obstetric hysterectomies were not necessary. Conclusion: Cervical inversion is a simple, cost-effective, and time-saving procedure for PPH management in placenta previa accreta/increta. It could become a routine procedure for preserving the uterus and fertility of affected women.International Journal of Gynecology & Obstetrics 10/2014; 128(2). DOI:10.1016/j.ijgo.2014.08.020 · 1.56 Impact Factor
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ABSTRACT: ContentsMares who have not delivered a foal early in life may experience limitations in cervical relaxation, primarily during oestrus. A closed cervix prevents intrauterine deposition of semen during natural breeding, may delay uterine clearance after insemination leading to intrauterine fluid accumulation in, and subsequent infertility. Therefore, a reliable pharmacological method of dilating the equine cervix would have practical application in veterinary medicine. The goal of this study was to investigate the effectiveness of topically applied, synthetic prostaglandin E1 analogue (PGE1) for stimulating dilation of the equine cervix. Ten mares in dioestrus were randomly assigned to one of two treatments in a single-blind crossover study: (treatment) PGE1 gel (1000 mcg compounded misoprostol cream) applied topically to the external cervical os (n = 5), and (control) a vehicle cream applied topically to the external cervical os (n = 5). Transrectal palpation and ultrasonographic measurements of the cervix were performed prior to, six and 24 h post-treatment. Digital measurements were taken, per vagina, at six and 24 h post-treatment. Mares were monitored through the subsequent oestrous cycle for ovulation. Mares were assigned to the opposite treatment group such that each mare served as her own control (crossover). Data were analysed using parametric (split-plot anova), as well as nonparametric (Kruskal–Wallis anova, Wilcoxon's rank-sum test) methods. At six and 24 h there were no significant differences for tone, length, height, degree of relaxation or echotexture between control and PGE1 treated groups at the measured time points (p > 0.05). Topical cervical application of PGE1 did not induce a measurable degree of cervical relaxation under the conditions of this experiment.Reproduction in Domestic Animals 10/2014; DOI:10.1111/rda.12435 · 1.18 Impact Factor
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ABSTRACT: Application of focused ultrasound stimulation (FUS) to the rat cervix during pregnancy has significant physiologic effects. One-millisecond-long pulses of 680-kHz ultrasound with a repetition frequency of 25 Hz, at ISPTA (spatial-peak, temporal-average intensity) of 1, 2 and 4W/cm(2), were applied to the rat abdomen over the cervix. FUS produced a significant change in cervical elasticity known as softening, which is part of the ripening process, comparable to the degree seen just before delivery. Timed-pregnant Sprague-Dawley rats (n = 40) were used. During gestation, the FUS system was applied to the cervix for variable times up to 1 h. Daily measurements of cervix light-induced florescence were made to estimate changes in softening. In addition, cervical stretch estimates of softening were made of isolated cervices of control and FUS-treated rats to measure distensiblity. The ultrasound power with ISPPA (spatial-peak, pulse-average intensity) of 40 W/cm(2) was considered tolerable; the U.S. Food and Drug Administration regulatory limit is 190 W/cm(2) for both the body periphery and the fetus. This is the first report of alterations induced by ultrasound in the connective tissue of the cervix and suggests the therapeutic application of ultrasound for the facilitation of labor and delivery.Ultrasound in Medicine & Biology 06/2014; 40(9). DOI:10.1016/j.ultrasmedbio.2014.02.028 · 2.10 Impact Factor