Cervical insufficiency: re-evaluating the prophylactic cervical cerclage.

Historically, placement of a cervical cerclage was based almost entirely on the obstetrical history. Over the past two decades however, we have recognised that history alone may not be the only indication for cerclage but rather, complementing the obstetrical history with ultrasonographic and biochemical findings may better identify those women who may benefit most from the placement of a cervical cerclage. Review of the literature appears to suggest that the best approach towards the management of a cervical insufficiency is to first categorise women as being either high risk of low risk-based on obstetrical history. Although women with an obstetrical history of at least three 2nd trimester losses are likely to benefit from a prophylactic cerclage than those without this history may better be managed with progesterone and serial cervical length measurements. This approach can in turn be used to identify those women with early cervical shortening that may require an emergency cerclage. Although randomised controlled trials are still lacking, recent studies suggests that this approach may be more effective especially when combined with markers of intra-amniotic inflammation. As for the prophylactic cerclage itself, with the abdominal cerclage being less invasive given the possibility of a laparoscopic placement, it may prove to be a more effective alternative to the conventionally placed McDonald cerclage. This however, remains to be evaluated more carefully.

Predicting outcome after emergent cerclage using classification tree analysis.

We sought to develop a predictive model for gestational age at delivery after placement of an emergent cerclage in the second trimester. Data were obtained for women undergoing emergent cerclage in response to documented cervical change on physical examination at a university hospital between 1980 and 2000. Hierarchically optimal classification tree analysis (CTA) was used to predict delivery prior to 24 weeks, between 24 and 27 6/7 weeks, or after 27 6/7 weeks. One hundred sixteen women were available for analysis. Delivery prior to 24 weeks was best predicted by presence of prolapsed membranes and gestational age at cerclage placement; delivery between 24 and 27 6/7 weeks was best predicted by parity alone; delivery of at least 28 weeks was best predicted by cervical dilation and length, presence of prolapsed membranes, and parity. When choosing a single model to predict delivery at the three different gestational age periods, the last model yielded the most accurate results. CTA can be used to construct a predictive model for outcome after emergent cerclage that may be informative for both patients and physicians.

The length of the cervix and the risk of spontaneous premature delivery. National Institute of Child Health and Human Development Maternal Fetal Medicine Unit Network.

BACKGROUND: The role of the cervix in the pathogenesis of premature delivery is controversial. In a prospective, multicenter study of pregnant women, we used vaginal ultrasonography to measure the length of the cervix; we also documented the incidence of spontaneous delivery before 35 weeks' gestation. METHODS: At 10 university-affiliated prenatal clinics, we performed vaginal ultrasonography at approximately 24 and 28 weeks of gestation in women with singleton pregnancies. We then assessed the relation between the length of the cervix and the risk of spontaneous preterm delivery. RESULTS: We examined 2915 women at approximately 24 weeks of gestation and 2531 of these women again at approximately 28 weeks. Spontaneous preterm delivery (at less than 35 weeks) occurred in 126 of the women (4.3 percent) examined at 24 weeks. The length of the cervix was normally distributed at 24 and 28 weeks (mean [+/- SD], 35.2 +/- 8.3 mm and 33.7 +/- 8.5 mm, respectively). The relative risk of preterm delivery increased as the length of the cervix decreased. When women with shorter cervixes at 24 weeks were compared with women with values above the 75th percentile, the relative risks of preterm delivery among the women with shorter cervixes were as follows: 1.98 for cervical lengths at or below the 75th percentile (40 mm), 2.35 for lengths at or below the 50th percentile (35 mm), 3.79 for lengths at or below the 25th percentile (30 mm), 6.19 for lengths at or below the 10th percentile (26 mm), 9.49 for lengths at or below the 5th percentile (22 mm), and 13.99 for lengths at or below the 1st percentile (13 mm) (P < 0.001 for values at or below the 50th percentile; P = 0.008 for values at or below the 75th percentile). For the lengths measured at 28 weeks, the corresponding relative risks were 2.80, 3.52, 5.39, 9.57, 13.88, and 24.94 (P < 0.001 for values at or below the 50th percentile; P = 0.003 for values at the 75th percentile). CONCLUSIONS: The risk of spontaneous preterm delivery is increased in women who are found to have a short cervix by vaginal ultrasonography during pregnancy.

Cervical incompetence.

In the early 1950s, when treatment of cervical incompetence was first described, diagnosis seemed relatively simple and management favorable, but after more than 35 years of trying multiple variations of procedures and treatment regimens, no advances have been made. In 1959, Neser questioned the very existence of cervical incompetence as an entity, and concluded that, in the final analysis, the problem is a diagnostic one. Liberal use of cerclage in situations of moderate risk of preterm delivery or as a prophylactic measure for multiple gestation does not appear to improve outcome, as judged by prematurity or survival. Because of advances in neonatal care in the last decade, fetal survival has improved tremendously. It is hoped that, in the future, more objective and accurate criteria for the diagnosis of cervical incompetence will emerge, and that outcome of treatment will be measured not by fetal survival, but by prolongation of pregnancy and by birth weight. At present, making an unequivocal diagnosis of cervical incompetence remains an elusive, challenging, and unsolved problem.

Cervical incompetence. A diagnostic and prognostic scoring system.

Recognition of the incompetent cervical as a cause of midtrimester abortion and prematurity has led to the development of surgical methods of repair. Diagnosis of the condition has generally relied on clinical findings and historical information from the patient. A scoring system based on clinical and historical criteria is suggested for selection of patients for surgical correction. Thirty-one cases of cervical incompetence tested surgically over the past 10 years are reviewed. Patients who had higher scores had a higher postoperative pregnancy success rate than the patients with lower scores. The scoring of patients preoperatively appears useful for selection of patients as well as prognostically.