Very short cervix in low‐risk asymptomatic singleton pregnancies: Outcome according to treatment and cervical length at diagnosis

The aim of this study was to explore the outcome of low‐risk singleton pregnancies with very short cervical length (CL ≤15 mm) according to method of treatment and CL at diagnosis. Material and methods Retrospective study on singleton pregnancies devoid of risk factors for spontaneous preterm delivery identified in the course of universal screening programs by vaginal sonography at 20‐24 weeks of gestation to have very short CL ≤ 15 mm. Results The study group consisted of 233 pregnancies with CL ≤ 15 mm of which 88 had cervical cerclage inserted and the remaining 145 were treated with vaginal progesterone. Mean CL at diagnosis was significantly shorter in the cerclage group (5 mm) compared with the progesterone group (12 mm). Regardless of treatment there was no difference in the rate of spontaneous preterm delivery at <32 weeks of gestation in women with CL ≥ 9 mm at screening (11% and 12% in the cerclage and progesterone groups, respectively). In contrast, in the subgroup with CL ≤ 8 mm cervical cerclage resulted in significantly lower rates of spontaneous preterm delivery at <32 weeks of gestation compared with progesterone treatment (20% and 45%, respectively, P  = .009) and the median gestational age at birth was significantly greater (37 weeks vs 36 weeks, respectively, P  = .013). Conclusions The majority of asymptomatic singleton pregnancies with short CL will remain undelivered until 32 weeks of gestation whether treated with progesterone or cerclage. Women with extreme cervical shortening appear to benefit more from cervical cerclage.