(500) Predictors of Pregnancy Duration and Gestational Age at Delivery after Laser Photocoagulation for Twin-Twin-Transfusion Syndrome

Thursday, January 30, 2025

4:00 PM – 6:00 PM

Submitting Author and Presenting Author(s)

Henry L. Galan, MD

Professor, Maternal Fetal Medicine
University of Colorado, School of Medicine, Children's Hospital of Colorado
Aurora, Colorado, United States

Coauthor(s)

Michael V. Zaretsky, MD (he/him/his)

Professor, Maternal Fetal Medicine
University of Colorado, School of Medicine
Aurora, Colorado, United States
Stephen P. Emery, MD (he/him/his)

Professor of Obstetrics, Gynecology, and Reproductive Sciences
University of Pittsburgh School of Medicine
Pittsburgh, Pennsylvania, United States
ZP

Zhaoxing Pan, PhD

Associate Professor
University of Colorado
Aurora, Colorado, United States
NB

Nicholas Behrendt, MD

University of Colorado
Aurora, Colorado, United States
SD

Sarkis C. Derderian, MD

Assistant Professor, Surgery
University of Colorado, School of Medicine
Aurora, Colorado, United States
Anthony Johnson, DO

Professor
McGovern Medical School University of Texas Health Science Center at Houston (UThealth)
Houston, Texas, United States
Greg Ryan, MD

Head, Fetal Medicine program & Ontario Fetal Centre
University of Toronto
Toronto, Ontario, Canada
William H. Goodnight, MD (he/him/his)

Associate Professor of Maternal Fetal Medicine
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Objective: Limited data exist regarding the impact of perioperative factors on pregnancy duration after fetoscopic laser photocoagulation (FLP) for twin-twin transfusion syndrome (TTTS). The objective of this study was to determine the best predictors of duration of pregnancy (latency) and gestational age (GA) at delivery following FLP for TTTS.

Study Design: TTTS cases treated with FLP between 2001-2023 were identified through the North American Fetal Therapy Network monochorionic twin registry containing perioperative variable and pregnancy outcomes. Higher order multiples, fetal anomalies and karyotypic abnormalities were excluded. Multiple p</span>erioperative variables were analyzed to determine the best predictors of latency and GA at delivery. Kaplan-Meier and COX regression were used in univariate analysis to identify significant factors that then had interplay evaluation with multiple Cox regression to determine the best predictors.

Results: Of 2317 TTTS cases treated with FLP, 1740 met inclusion criteria with sufficient information for analysis. Shown as Mean ± S.D, the GA at time of laser was 20.7±2.7 wks, the procedure time was 52.5±25.5 min, the latency period was 10.2±5.3 wks and GA at delivery was 30.8±4.9 wks. While univariate analysis found multiple factors significantly associated with both reduced latency (Table) and earlier delivery GA, Cox regression analysis (N=865) showed the best predictors to be cervical length (CL) of < 25mm, amnioinfusion volume, laser time and earlier GA at time of FLP (Table). Early GA at time of surgery carried longer latency to delivery (Figure) but resulted in earlier delivery. The longer latency with early surgery persists regardless of whether CL is < or ≥ 25mm (Figure). The hazard to early delivery GA decreased by 4.3% if surgery occurs a week later as opposed to a week earlier.

Conclusion: From this large registry, the best predictors of both latency and GA at delivery after FLP for TTTS are the GA at time of the procedure, laser time, a short cervix and volume of amnioinfusion during FLP. These are factors to consider in the management of TTTS.