CASE A woman with recurrent pregnancy loss
A 38-year-old woman (G4P0221) presents to your office for preconception counseling. Her history is significant for the following: a spontaneous pregnancy loss at 15 weeks’ gestation; a pregnancy loss at 17 weeks secondary to preterm premature rupture of membranes (PPROM); a cesarean delivery at 30 weeks and 6 days’ gestation after placement of a transvaginal cerclage at 20 weeks for cervical dilation noted on physical exam (the child now has developmental delays); and most recently a delivery at 24 weeks and 4 days due to preterm labor with subsequent neonatal demise (this followed a transvaginal cerclage placed at 13 weeks and 6 days).
How would you counsel this patient?
Cervical insufficiency describes the inability of the cervix to retain a pregnancy in the absence of the signs and symptoms of clinical contractions, labor, or both in the second trimester.1 This condition affects an estimated 1% of obstetric patients and 8% of women with recurrent losses who have experienced a second-trimester loss.2
Diagnosis of cervical insufficiency is based on a history of painless cervical dilation after the first trimester with expulsion of the pregnancy in the second trimester before 24 weeks of gestation without contractions and in the absence of other pathology, such as bleeding, infection, or ruptured membranes.1 Diagnosis also can be made by noting cervical dilation on physical exam during the second trimester; more recently, short cervical length on transvaginal ultrasonography in the second trimester has been used to try to predict when a cervical cerclage may be indicated, although sonographic cervical length is more a marker for risk of preterm birth than for cervical insufficiency specifically.1,3
Given the considerable emotional and physical distress that patients experience with recurrent second-trimester losses and the significant neonatal morbidity and mortality that can occur with preterm delivery, substantial efforts are made to prevent these outcomes by treating patients with cervical insufficiency and those at risk for preterm delivery.
Transvaginal cerclage: A treatment mainstay
Standard treatment options for cervical insufficiency depend on the patient’s history. One of the treatment mainstays for women with prior second-trimester losses or preterm deliveries is transvaginal cervical cerclage. A transvaginal cerclage can be placed using either a Shirodkar technique, in which the vesicocervical mucosa is dissected and a suture is placed as close to the internal cervical os as possible, or a McDonald technique, in which a purse-string suture is placed around the cervicovaginal junction. No randomized trials have compared the effectiveness of these 2 methods, but most observational studies show no difference, and one suggests that the Shirodkar technique may be more effective in obese women specifically.4-6
Indications for transvaginal cerclage. The indication for transvaginal cerclage is based on history, physical exam, or ultrasonography.
A physical-exam indication is the most straightforward of the 3. Transvaginal cerclage placement is indicated if on physical exam in the second trimester a patient has cervical dilation without contractions or infection.1,7
A history-indicated cerclage (typically placed between 12 and 14 weeks’ gestation) is based on a cerclage having been placed in a prior pregnancy due to painless cervical dilation in the second trimester (either ultrasonography- or physical-exam indicated), and it also can be considered in the case of a history of 1 or more second-trimester pregnancy losses related to painless cervical dilation.1
More recent evidence suggests that in patients with 1 prior second-trimester loss or preterm delivery, serial sonographic cervical length can be measured safely from 16 to 24 weeks, with a cerclage being placed only if cervical length decreases to less than 25 mm. By using the ultrasonography-based indication, unnecessary history-indicated cerclages for 1 prior second-trimester or preterm birth can be avoided in more than one-half of patients (FIGURE 1).1,7
Efficacy. The effectiveness of transvaginal cerclage varies by the indication. Authors of a 2017 Cochrane review found an overall reduced risk of giving birth before 34 weeks’ gestation for any indication, with an average relative risk of 0.77.2 Other recent studies showed the following8-10:
- a 63% delivery rate after 28 weeks’ gestation for physical-exam indicated cerclages in the presence of bulging amniotic membranes
- an 86.2% delivery rate after 32 weeks’ gestation for ultrasonography-indicated cerclages
- an 86% delivery rate after 32 weeks’ gestation for a history-indicated cerclage in patients with 2 or more prior second-trimester losses.
Success rates, especially for ultrasonography- and history-indicated cerclage, are thus high. For the 14% who still fail these methods, however, a different management strategy is needed, which is where transabdominal cerclage comes into play.
Continue to: Transabdominal cerclage is an option for certain patients...