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CME Credit Offered
CME Credit Offered
Abstract Award
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Poster Session 3

(868) Fetal pleural effusions: natural history and response to interventions

Friday, January 31, 2025
10:30 AM – 12:30 PM  

    Submitting Author and Presenting Author(s)

  • Natalie B. Gulrajani (she/her/hers)

    University of California, San Francisco, School of Medicine
    San Francisco, California, United States

    • Coauthor(s)

  • Teresa N. Sparks, MD, MS (she/her/hers)

    Associate Professor, Maternal-Fetal Medicine and Clinical Genetics
    Center for Maternal-Fetal Precision Medicine, University of California San Francisco
    San Francisco, California, United States

  • Juan Gonzalez, MD, MS, PhD (he/him/his)

    Perinatologist Division Director, Maternal-Fetal Medicine & Reproductive Genetics Director, Center f
    Center for Maternal-Fetal Precision Medicine, University of California San Francisco
    San Francisco, California, United States

Objective: Primary fetal pleural effusions (FPEs) require close surveillance, and thoracentesis or thoracoamniotic shunts are often considered for management. However, it can be challenging to predict which FPEs will evolve or respond to interventions. We aimed to analyze the prenatal course of primary FPEs and response to interventions.

Study Design: Retrospective cohort study of pregnancies with primary fetal FPEs referred to our center between 2017-2024. We included isolated unilateral FPEs or asymmetric bilateral FPEs with one side dominant. All ultrasound reports and records were reviewed for the course of the FPEs, other complications, fetal interventions, and relevant test results. Each case was categorized as improved or resolved FPE, stable FPE, or worsened FPE (including progression to non-immune hydrops fetalis).

Results: Among 24 cases identified, 9 underwent thoracentesis and/or thoracoamniotic shunt. Median gestational age at diagnosis and first intervention was 19.4 and 20.7 weeks, respectively, for cases with an intervention. A majority (60%) of cases without intervention improved or remained stable (Table). All 9 cases with intervention had additional markers of severity (i.e. mediastinal shift or ascites), compared to only 53% (8/15) without intervention. Each case with an intervention had a thoracentesis, 44% (4/9) had more than one thoracentesis, and 33% (3/9) later had thoracoamniotic shunt placement (Fig). FPEs were chylous in 63% (5/8) of sampled cases; 60% (3/5) of chylous and all (3/3) serous effusions improved after intervention. All cases had a negative viral workup, and among 22 cases that underwent genetic screening and 13 that had diagnostic testing including exome sequencing, only 1 case was identified to have fetal trisomy 21.

Conclusion: Many primary FPEs improved or resolved spontaneously without intervention, and genetic diagnoses were uncommon. Most cases requiring intervention responded to thoracentesis and few ultimately required a thoracoamniotic shunt. These data are useful for anticipating the course of and response to interventions among these complicated pregnancies.