Rate of preterm delivery and latency period in asymptomatic patients undergoing cerclage for very short cervix ≤10.0 mm

Abstract

AimTo estimate the rate of preterm delivery (PTD) and mean latency period to delivery in asymptomatic women with no history of preterm delivery and cervical length (CL) ≤10.0 mm undergoing or not cerclage and who were not treated with vaginal progesterone. MethodsRetrospective analysis of asymptomatic patients with singleton pregnancies and no history of preterm delivery, with an incidental finding of a CL ≤10.0 mm measured with transvaginal ultrasound during the mid-trimester scan, 56 of them (63.6%) underwent cerclage placement and 32 (36.4%) did not, none of them received vaginal progesterone. Those with evidence of advanced dilation, prolapsing, membranes, ruptured membranes, or positive signs of infection were not candidates for cerclage placement were excluded from the analysis. Differences in the prevalence of preterm birth, mean gestational age at delivery, and mean latency from very short cervix identification to delivery between the two groups were calculated. Associations between cerclage and preterm delivery adjusted for maternal characteristics and fetal weight, were estimated. ResultsMedian (range) gestational age at time of CL measurement in the cerclage group was (weeks/days) 20w6d (17w5d–23w3d) vs. 21w5d (17w6d–23w6d) in the no-cerclage group (p=0.02). No differences in CL were observed between those who had a cerclage (5.9 mm (SD 3.1 mm)) vs. those who did not (6.5 mm (SD 3.2 mm); p=0.4). The prevalence of preterm delivery (PTD) in women with cerclage vs. women without cerclage was: PTD <37 weeks 31/56 (55.3%) vs. 28/32 (87.5%); adjusted (a) OR 0.17 (95% CI; 0.05-0.62 p=0.008); PTD ≤34 weeks 27/56 (48.2%) vs. 24/32 (75.0%); aOR 0.16 (95% CI 0.05-0.55; p=0.02); PTD ≤28 weeks 19/56 (33.9%) vs. 22/32 (68.7%); aOR 0.15 (95% CI 0.05-0.51; p=0.002). The mean (range) gestational age at delivery was 32w6d (19w1d–40w1d) for the cerclage group, and 28w1d (20w1d–40w2d) for the no-cerclage group (p =0.001). The median (range) latency from the time of CL measurement to delivery in the cerclage group was 84 (8-144) vs. 43 (1-146) days in the no-cerclage group (p=0.003). ConclusionAmong low-risk asymptomatic women with a very short cervix (≤10.0 mm) in the midtrimester scan, those treated with cerclage have increased latency to delivery and lower prevalence of preterm birth as compared to expectant management.