Indomethacin and Cefazolin for Physical Exam-Indicated Cerclage to Improve Latency: A Protocol Validation Study

A single-center randomized trial showed improved latency with use of indomethacin and cefazolin (I/C) during and following exam-indicated cerclage (EIC). The same center recently published a pre/post comparison demonstrating similar results. This research aimed to validate the protocol in a different setting.Retrospective cohort study of singleton pregnancies undergoing EIC at a single center between 2013 and 2022. EIC was performed for painless cervical dilation between 16 and 23 weeks' gestation with dilation ≥1 cm. Exposure was defined as receipt of I/C during and following EIC. The primary outcome was latency ≥ 28 days after cerclage placement. Secondary outcomes included latency; gestational age at delivery; delivery ≤ 28 weeks; preterm premature rupture of membranes; intra-amniotic infection (IAI); and median birth weight. Bivariate statistics were used to analyze data; multivariable regression analyses were used to control for confounders (progesterone use, cervical dilation at time of cerclage placement, history of preterm birth, and prolapsing membranes).EIC was placed in 81 pregnancies and 48 (59%) received I/C. Baseline characteristics did not differ between groups, except that prolapsing membranes were significantly less likely in patients receiving I/C (6.2 vs. 21.2%; p = 0.04). Latency ≥ 28 days occurred in 90% of I/C recipients and 82% of the controls (p = 0.32); this difference remained nonsignificant after controlling for confounders (adjusted relative risk: 1.02 [95% confidence interval: 0.85, 1.21]). I/C recipients had lower rates of IAI (4.2 vs. 24.2%, p = 0.007), even after adjustment (adjusted relative risk: 0.18 [95% confidence interval: 0.04, 0.74]). Other secondary outcomes did not differ.Use of I/C at the time of EIC at this center was not associated with increased latency to delivery (albeit in a small cohort) but was associated with lower rates of intra-amniotic infection. Larger-scale validation studies would be helpful to confirm the value of this intervention. · Indomethacin/cefazolin (I/C) increased latency for exam-indicated cerclage in a trial.. · We performed an observational comparison to validate these findings.. · I/C use for exam-indicated cerclages was associated with decreased intra-amniotic infection.. · I/C was not associated with change in latency.. · Larger-scale validation studies needed to confirm the value of intervention..