Amniocentesis and Therapeutic Amnioreduction Before Rescue Cerclage: Improving Patient Selection for Rescue Cerclage based on Amniotic Fluid Screening

Abstract

Objectives

This study aimed to describe our protocol that recommends amniocentesis for intra-amniotic infection and/or inflammation (IAI) screening to guide rescue cerclage decision-making.

Methods

We implemented a novel protocol at our centre in 2021, which recommends performing amniocentesis when exam-indicated cerclage is recommended (singleton or multiple pregnancies between 14 and 23⁶ weeks gestational age (GA), with cervical dilation <4 cm and exposed membranes at or beyond the external cervical os). Amniotic fluid is tested for interleukin (IL)-6, glucose, white count, Gram-stain, and amniotic fluid cultures. We retrospectively reviewed records and reported outcomes such as interval from amniocentesis to delivery (ADI), GA at delivery, and perinatal survival for patients with low versus high IL-6 levels.

Results

From 25 patients included, 12 had low IL-6 (<3000 pg/mL) (11 received rescue cerclage), while 13 had high IL-6 (≥3000 pg/mL) and were managed with antibiotics and progesterone. The low IL-6 group showed a significantly longer mean ADI (85⁵ ± 43² days vs. 21⁶ ± 14⁵ days, P = 0.0003) and higher mean GA at delivery (33² ± 6² weeks vs. 23⁶ ± 2⁶ weeks, P = 0.0003). 91.7% of patients with low IL-6 survived to discharge, compared to 46.2% in the high IL-6 group (P = 0.03). Most high IL-6 patients delivered within 3 to 5 weeks despite treatment.

Conclusion

Amniocentesis before cerclage, particularly IL-6 screening, is a valuable tool in guiding the decision to perform rescue cerclage in selected patients. IL-6 is a strong predictor of both the likelihood of successful cerclage and perinatal outcomes. More studies are needed to optimize management for patients with a high risk of IAI.