Clinical meaning
At the NP level, managing cervical insufficiency requires understanding the evidence-based criteria for cerclage versus progesterone therapy. Cervical remodeling in insufficiency involves premature activation of matrix metalloproteinases (MMP-1, MMP-8) that degrade collagen, combined with increased hyaluronic acid and decreased proteoglycan content in the cervical stroma. Progesterone maintains cervical rigidity by suppressing MMP expression and maintaining the collagen-rich extracellular matrix. The OPPTIMUM trial showed vaginal progesterone reduced preterm birth in women with short cervix (<25 mm); the Berghella meta-analysis confirmed that cerclage reduces preterm birth in singleton pregnancies with short cervix AND prior preterm birth. The decision algorithm stratifies by history (prior preterm birth), cervical length, and number of fetuses to select progesterone, cerclage, or both.
Diagnosis & workup
Diagnostics & workup: - Serial transvaginal cervical length measurements every 1-2 weeks from 16-24 weeks in high-risk patients - Cervical length <25 mm triggers intervention in singleton with prior PTB; <20 mm is more concerning in women without prior PTB - Fetal fibronectin (fFN): negative test has >99% NPV for delivery within 14 days; useful in symptomatic patients 22-34 weeks - TVUS findings: cervical funneling (Y, V, or U-shaped internal os), dynamic cervical change with transfundal pressure - Amniocentesis if rescue cerclage considered: rule out subclinical intraamniotic infection (glucose <14 mg/dL, elevated WBC, positive culture suggest infection) - Preoperative labs before cerclage: GBS status, STI screening (gonorrhea, chlamydia), wet mount, urinalysis, CBC