Effect of intra-amniotic fluid pressure from polyhydramnios on cervical length in patients with twin-twin transfusion syndrome undergoing fetoscopic laser surgery

Ultrasound Obstet Gynecol. 2019 Dec;54(6):774-779. doi: 10.1002/uog.20228.

Abstract

Objectives: To determine the relationship between intra-amniotic pressure and cervical length (CL) in patients with twin-twin transfusion syndrome (TTTS) undergoing fetoscopic laser photocoagulation (FLP), and to identify pre- or intraoperative factors associated with increased intra-amniotic pressure in this population.

Methods: This was a prospective cohort study of patients undergoing FLP for TTTS. Exclusion criteria were triplet or higher-order gestation and prior cervical cerclage, amnioreduction or FLP procedure. CL was assessed using preprocedure transvaginal ultrasound. Intra-amniotic pressure measurements were obtained on initial placement of the trocar into the amniotic cavity, using a direct hydrostatic pressure gauge. The relationship between intra-amniotic pressure and CL was assessed using multivariate linear regression analysis, including relevant preoperative and intraoperative variables.

Results: In total, 283 pregnancies met the inclusion criteria. Quintero stage of TTTS was I in 33 pregnancies, II in 88, III in 150 and IV in 12. Mean gestational age (GA) at FLP was 20.7 ± 3 weeks. Mean intra-amniotic pressure was 23.1 ± 9 mmHg. On unadjusted linear regression analysis, there was no significant association between intra-amniotic pressure and preoperative CL (P = 0.24) or GA at delivery (P = 0.22). On multivariate analysis, the factors associated significantly with intra-amniotic pressure were: number of prior term deliveries (P = 0.03), recipient maximum vertical pocket (P < 0.0001), Quintero stage IV (P = 0.01) and type of anesthesia (sedation vs general anesthesia; P = 0.01).

Conclusion: In pregnancies with TTTS, intra-amniotic pressure is not associated with CL or GA at delivery. This novel finding suggests that cervical shortening in this population is not mechanically driven. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Keywords: amniotic fluid; cervical length; fetoscopy; laser photocoagulation; twin pregnancy; twin-twin transfusion syndrome.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Amniotic Fluid / physiology*
  • Cervical Length Measurement / methods*
  • Cervical Length Measurement / trends
  • Cervix Uteri / anatomy & histology
  • Cervix Uteri / diagnostic imaging
  • Female
  • Fetofetal Transfusion / diagnostic imaging
  • Fetofetal Transfusion / surgery*
  • Fetoscopy / methods*
  • Fetoscopy / trends
  • Gestational Age
  • Humans
  • Laser Coagulation / methods
  • Polyhydramnios / physiopathology*
  • Pregnancy
  • Pregnancy, Twin
  • Pressure
  • Prospective Studies
  • Treatment Outcome
  • Ultrasonography, Doppler, Color / methods