(1014) Adverse Perinatal Outcomes Based on Gestational Surrogacy Status in a Large Integrated Healthcare System

Friday, January 31, 2025

4:00 PM – 6:00 PM

Coauthor(s)

Fagen Xie, PhD (he/him/his)

Kaiser Permanente Southern California
Department of Research & Evaluation, Kaiser Permanente Southern California/Pasadena, California, United States
TI

Theresa M. Im, MPH

Kaiser Permanente Southern California
Department of Research & Evaluation, Kaiser Permanente Southern California/Pasadena, California, United States
DP

Daniella Park, MPH

Kaiser Permanente Southern California
Department of Research & Evaluation, Kaiser Permanente Southern California/Pasadena, California, United States
VC

Vicki Y. Chiu, MS

Programer/Analyst
Kaiser Permanente Southern California
Department of Research & Evaluation, Kaiser Permanente Southern California/Pasadena, California, United States
MF

Michael J. Fassett, MD

Kaiser Permanente West Los Angeles Medical Center
Department of Obstetrics & Gynecology, Kaiser Permanente West Los Angeles Medical Center/Los Angeles, California, United States

Submitting Author and Presenting Author(s)

Darios Getahun, MD, PhD, MPH (he/him/his)

Research Investigator II MD/Associate Professor
Kaiser Permanente Southern California, Department of Research & Evaluation / Kaiser Permanente Bernard J. Tyson School of Medicine, Department of Health Systems Science
Department of Research & Evaluation, Kaiser Permanente Southern California/Pasadena, CA, United States

Objective: To examine adverse perinatal outcomes by gestational surrogacy status in a large integrated healthcare system in the United States.

Study Design: We performed a retrospective cohort study among pregnant individuals receiving obstetrical care at Kaiser Permanente (KP) Southern California (01/01/2008–12/31/2023). Unstructured clinical notes abstracted from electronic health records were used to determine surrogate pregnancy status via natural language processing (NLP) validated by manual chart reviews. Births at < 20 weeks gestation were excluded from all analyses. Adjusted risk ratios (aRR) and 95% confidence intervals (CI) derived from robust Poisson regression described the associations.

Results: Among 636,300 pregnancies during the study period, 1,109 (0.17%) were identified as surrogate pregnancies. Compared to those with non-surrogate pregnancy, people with gestational surrogacy were more likely to be older (32.4% versus 19.4%), non-Hispanic white (39.0% versus 23.8%), have privately funded KP membership (19.8% versus 7.6%), and have multiple gestations (15.8% versus 1.6%). They were also less likely to smoke (0.7% versus 2.4%) and consume alcohol (19.0% versus 27.1%) during pregnancy. Gestational surrogacy was associated with significantly increased risk of placenta previa (aRR: 1.74, 95% CI: 1.44-2.10), placental abruption (aRR: 2.25, 95% CI: 1.45-3.50) and preterm birth (aRR: 1.27, 95% CI: 1.13-1.43) while with significantly decreased risk of small for gestational age/intrauterine growth restriction (aRR: 0.80, 95% CI: 0.69-0.93), premature rupture of membranes (aRR: 0.72, 95% CI: 0.53-0.98), gestational diabetes (aRR: 0.84, 95% CI: 0.72-0.98) and chorioamnionitis (aRR: 0.58, 95% CI: 0.40-0.86) (Table).

Conclusion: This study successfully leveraged unstructured data to identify surrogate pregnancies via NLP in a large integrated healthcare system. Placenta previa, placental abruption, and preterm birth were found to be associated with gestational surrogate pregnancy. Identifying these risk factors can provide empirical evidence for predicting and preventing adverse perinatal outcomes.