Published on October 25, 2009
cervical incompetence : Dr.Mohammed Abdalla Domiat general hospital cervical incompetence Slide 2: The cervix is said competent when it retains pregnancy till term. if not it is considered incompetent. Slide 3: Mostly incompetence is idiopathic but it may be secondary to anatomical, traumatic, or congenital connective tissue disorder. Slide 4: Although the efficacy of cerclage for cervical incompetence has never been fully confirmed in randomized clinical trials, the role of cerclage has been expanded to include women with “risk factors” for spontaneous preterm birth or nonreassuring sonographic cervical findings in the mid trimester. Slide 5: So before you send your patient to the theater for cerclage your diagnosis necessities solid criteria. Slide 6: But unfortunately there is no consensus about the cervical cut off length as most literatures failed to state a discriminatory cervical length, which varied widely between 15-25mm. in singleton pregnancy Slide 7: Cervical cut off length in singleton pregnancy is much more than in multiple pregnancy. Slide 8: Risk with CL <25 mm in twin pregnancies is similar to the risk with CL <15 mm in singleton pregnancies (52%( Slide 9: 4% 35% Slide 10: This wide variation in discriminatory cervical length will result in the categorization of 5% to 10% of pregnant women as having a short cervix. Slide 11: As any controversial issue we have here white and black faces but always within the grey zone, which lies in between, we fall in doubt. Slide 12: White face here is the women with irrelevant obstetric and gynecological history, as they need no screening. Slide 13: But those who have three or more midtrimester losses or preterm births represent the black face of the problem and the decision is a prophylactic cerclage performed at 13 to 16 weeks of gestation . Slide 14: The grey zone represented here by those women of low or moderate risk, and they need an ultrasound screening by transvaginal ultrasonography. Ultrasound screening : Ultrasound screening if we are going to screen this group of patients with mild to moderate risk : when to start? what is the ultrasonic criteria of incompetent cervix? and when to intervent? when to start : when to start TVS should not begin before 16 weeks as the upper portion of the cervix is not easily distinguished ultrasonic criteria of incompetent cervix : ultrasonic criteria of incompetent cervix Make sure to use proper technique. Knowing what to measure . Know what's normal, and what's abnormal . Linking cervical assessment to gestational age . proper technique : proper technique patients are asked to empty their bladder . the vaginal probe, which is advanced in the anterior fornix until a midline sagittal view of the cervix and lower uterine segment and the internal os, external os, cervical canal, and endocervical mucosa, are identified the probe is slowly withdrawn as excessive pressure with the probe may elongate the cervix. The cervical length is measured by freezing the screen three separate times with no more than 2 to 3 mm variations. Funneling can only be recognized by being certain that the walls of the funnel are formed by endocervical mucosa. If the cervical canal is sometimes curved, therefore, cervical length should be determined by tracing the length of the cervix or by adding the sum of two straight sections. Apply transfundal pressure for 15 seconds, and record any changes in cervical length or funneling. “cervical stress test” . Slide 20: “cervical stress test” what's normal : what's normal In low-risk women, CL during pregnancy has a mean of 35 to 40 mm from 14 to 30 weeks. the lower 10th percentile being 25 mm and the upper 10th (90th percentile) 50 mm. Slide 24: 38 1252 1998 Heath et al 42 175 1997 Tongsong et al 41 41 1996 Cook et al 35 2915 1996 Iams et al 37 106 1995 Iams et al 42 154 1994 Zorzoli et al 37 177 1993 Murakawa et al 42 77 1991 Andersen et al 48 24 1990 Kushnir et al 41 125 1990 Andersen et al 48 80 1988 Podobnik et al 52 150 1988 Ayers et al Cervical Length (mm) N Year Reference CERVICAL LENGTH (MEAN OR MEDIAN) IN LOW-RISK POPULATIONS IN MIDTRIMESTER what's abnormal? : The discriminatory length of cervical shortening varies widely between 25mm to 15mm what's abnormal? Slide 26: 97 47 99 8 ≤15 14–24 Hassan et al 99 52 99 58 ≤15 23 Heath et al 99 39 100 6 ≤25 18–22 Taipale et al 97 26 97 23 <20 24 Iams et al % NPV % PPV % Specificity % Sensitivity Cutoff (wks) Reference value of cervical sonography in the screening of preterm birth Slide 27: Low %PPV means that many undue cerclages were done. Slide 28: high %NPV means that the test is reassuring when negative. Slide 29: So we cannot rely on cervical length alone as a predictor of incompetence Slide 30: the progressive shortening detected by serial sonar, funneling (width and length), v-shaped lower uterine segment and dynamic cervical changes with fundal or suprapubic pressure. What are the most important? Slide 31: 1 2 3 4 Slide 32: bulging of the membranes in the vagina. The fetal lower limb protruded into the vagina. But how to avoid undue cerclage and how not to miss a case? : But how to avoid undue cerclage and how not to miss a case? Slide 34: RISK ASSESMENT >=3 unexplained second-trimester losses or preterm deliveries. Elective Cerclage at 14-16 wk. No risk factor routine ultrasound screening of the cervix is not recommended <3 unexplained second-trimester losses or preterm deliveries. routine ultrasound screening of the cervix is done at 16-20 wk. serial ultrasonographic changes consistent with a short cervix or evidence of funneling. Urgent cerclage if noted before fetal viability after fetal and maternal evaluation Slide 35: Can a Cervical Cerclage be Used to Prevent Preterm Delivery in Patients with a Short Cervix or Funneling? Slide 36: 26 31 16 Obstetrician uncertainty 1292 1993 MRC/RCOG 6.7 5.5 <28 Moderate risk of cervical incompetence 506 1984 Lazar et 34 32 18 High risk of cervical incompetence 194 1984 Rush et al. % Controls % Cerclage Weeks at Cerclage Indication N Reference Year Delivery <37 Weeks RANDOMIZED STUDIES OF ELECTIVE CERVICAL CERCLAGE RANDOMIZED STUDIES OF ELECTIVE CERVICAL CERCLAGE : results of randomized clinical trials suggest that cerclage either had a modest effect on reducing the rate of preterm delivery or no effect whatsoever. RANDOMIZED STUDIES OF ELECTIVE CERVICAL CERCLAGE Key points : Key points The high negative predictive value for preterm birth associated with a long cervix and with the absence of funneling has important clinical implications in symptomatic patients. Key points : Using TVU to assess CL is an effective way to predict PTB and "incompetent cervix," now better named cervical insufficiency. It's safe and patients accept the examination well. Key points Key points : Screening frequency should depend on severity of obstetric history, with serial TVU of the cervix having a better predictive accuracy than one, especially in high-risk populations. Key points Key points : the shorter the cervix, the higher the risk of PTB, and the earlier in gestational age at which the shortening occurs, the higher the risk. Key points Key points : screening high-risk women with TVU of the cervix and placement of a cerclage for the short or funneled cervix should not be considered standard care until proven by properly conducted, large randomized trials Key points Thank you : Thank you Urgent, or therapeutic, cerclage : Urgent, or therapeutic, cerclage for women who have serial ultrasonographic changes consistent with progressive shortening or evidence of cervical funneling. Urgent, or therapeutic, cerclage : ACOG Practice Bulletin No. 48November 2003 serial TVS should not begin before 16 weeks as the upper portion of the cervix is not easily distinguished Urgent, or therapeutic, cerclage Urgent, or therapeutic, cerclage : The anatomic cervical changes of dilation of the internal os, prolapse of the fetal membranes into the endocervical canal, shortening of the distal cervical segment, and exacerbation with transfundal pressure have been suggested as a final common pathway for multiple pathophysiologic processes. Urgent, or therapeutic, cerclage Transabdominal cerclage an alternative approach to the incompetent cervix : Transabdominal cerclage an alternative approach to the incompetent cervix Indications of transabdominal cerclage : Indications of transabdominal cerclage If cervix is absent or severely shortened, if congenital or traumatic defects if the transvaginal approach is not feasible or has failed. Slide 54: OR It is most often placed at 10 to 14 weeks gestation Timing of placement Preconception transabdominal cerclage placement Slide 55: has many practical benefits: easier . smaller incision. Safer to fetus. Can be done laparoscopically. Preconception transabdominal cerclage placement Slide 56: The overall live birth rate for prophylactic transabdominal cerclage approaches 90%, in whom transvaginal cerclage has been unsuccessful. When cerclage is performed on an emergent basis-rather than prophylactically-the success rate drops to less than 60% due to the increased risk of rupturing the membranes during the procedure or trapping the membranes below the level of the cerclage. cerclage placement Adverse effects : cerclage placement Adverse effects Slide 58: *Suture displacement, *rupture of membranes, *and chorioamnionitis are the most common complications associated with vaginal cerclage placement, Slide 59: *Transabdominal cerclage can be complicated by: rupture of membranes . chorioamnionitis. intraoperative hemorrhage. known risks associated with laparotomy. Slide 60: Life-threatening complications of uterine rupture and maternal septicemia are extremely rare but have been reported with all types of cerclage. Key points : Key points When a cervical length (CL) below 25 mm is found in low-risk women with an overall incidence of PTB of 4%, the positive predictive value (PPV) of CL is 18%. When the same 25 mm cut-off is used in high-risk patients with a history of PTB at less than 32 weeks with an overall incidence of PTB of 26%, PPV jumps to 55%. The most common gestational age at which a short cervix or funneling develops is 18 to 22 weeks. So if a screening program is to only include one CL assessment, perform it during this interval. While many women would be expected to have a PTB based solely on their histories, a CL at or above 35 mm between about 18 and 24 weeks was correlated with preterm delivery risk of only 4% in both high-risk singleton and twin gestations. Key points : Key points Key points : Key points Slide 64: the shorter the cervix at presentation, the higher the risk for preterm delivery. Slide 65: Can a Cervical Cerclage be Used to Prevent Preterm Delivery Slide 66: In whom is an urgent cerclage indicated?