Management of Cervical Insufficiency and Bulging Fetal Membranes
The loudest call to obstetricians regarding the complex problem of extreme prematurity should be for organization in our approach. We will need to start with common ground and by marking a moment in gestation when we should clearly focus on the problem of prematurity. Why don't we uniformly review a patient's obstetric history at 20 weeks and assess for history of spontaneous preterm birth and consider initiation of progesterone? Data from the NIH trial supports such an intervention at that gestational age.3 Systematic, universal screening of a patient's history at 20 weeks will improve rates of intervention and potentially lessen the incidence of preterm delivery.
Most practitioners also perform an ultrasound examination in the second trimester to screen for fetal malformations and assess gestational age. We know an assessment of cervical length can identify patients at greater risk for preterm delivery.4 Why don't we call for anomaly screens to be more uniformly performed at 20 weeks of gestation in low-risk women, with a transvaginal assessment of cervical length to be included in the evaluation?
The article by Daskalakis et al demonstrated transvaginal sonography at 18–23 weeks of gestation could reduce loss of life by the use of cervical cerclage in low-risk women. Is it now unethical to withhold information on cervical length from our patients to apprise them of their risk for extreme preterm birth with its associated morbidity and mortality? The editorialist calls for additional randomized trials. But will fully informed patients allow for randomization to bed rest when membranes are visible to verify the findings of this article if presented its data—a 40% reduction in mortality with intervention? In addition, a randomized trial with a similar patient population has already demonstrated benefit.5 Another published randomized trial in high-risk women has also observed benefit for cervical ultrasonography and cerclage.6 These studies appear to demonstrate that the following populations may benefit from cervical ultrasonography and indicated cerclage: 1) low-risk women with profound cervical change when membranes are visible and 2) high-risk patients with marked cervical change.
Future randomized trials can validate or refute these observations and attempt to better define sufficient cervical change for intervention. However, repeated, well-performed observational studies can also better define such populations. We could rationally suggest standardizing the timing and method of the second-trimester ultrasound scan. We could label the 20-week prenatal visit as the Prematurity Visit and systematically review the obstetric history and transvaginal radiographic data. Is it time for the Prematurity Visit? Who will decide when the time is right to organize? This time, obstetricians should.
We need a forum to discuss the ethics of screening for prematurity, methods, cost, and potential impact. We need a roadmap to reduce fetal/neonatal death related to extreme prematurity with defined goals, directed clinical research, and an action plan for implementing screening if criteria are met.