(559) Risk of Hemorrhage and Severe Maternal Morbidity (SMM) with Low-lying Placenta: A Nationwide Analysis

Thursday, January 30, 2025

4:00 PM – 6:00 PM

Submitting Author and Presenting Author(s)

May Abiad, MD (she/her/hers)

Postdoctoral Research Fellow
Maternal Fetal Care Center, Boston Children's Hospital
Boston, Massachusetts, United States

Coauthor(s)

Giulia Bonanni, MD

Postdoctoral Research Fellow
Postdoctoral Research Fellow Fetal Care and Surgery Center Division of Fetal Medicine and Surgery Boston Children's Hospital, Harvard Medical School
Boston, MA, United States
Anna M. Modest, MPH, PhD

Faculty Scientist
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
Ali Javinani, MD (he/him/his)

Postdoctoral Research Fellow
Boston Children's Hospital, Harvard Medical School
Boston, Massachusetts, United States
Nikan Zargarzadeh, MD

Research Fellow
Boston Children's Hospital, Harvard Medical School
Boston, Massachusetts, United States
George R. Saade, MD (he/him/his)

Professor and Chair, Associate Dean for Women's Health Obstetrics and Gynecology
Macon & Joan Brock Virginia Health Sciences Eastern Virginia Medical School at Old Dominion University
Norfolk, Virginia, United States
Scott A. Shainker, DO

Associate Professor of Obstetrics, Gynecology, and Reproductive Biology
Maternal Fetal Care Center Associate Professor of Surgery Associate Professor of Obstetrics, Gynecology and Reproductive Biology Harvard Medical School
Boston, Massachusetts, United States
Kjersti M. Aagaard, MD, PhD

Medical Director, HCA Healthcare and HCA Research Institute
Boston Children’s Hospital, Division of Fetal Medicine and Surgery, Boston, MA; HCA Healthcare and HCA Healthcare Research Institute, Nashville, TN; HCA Texas Maternal Fetal Medicine, Houston, TX; Baylor College of Medicine and Texas Children's Hospital, Houston, TX
Tomball, Texas, United States
Alireza A. Shamshirsaz, MD (he/him/his)

Department Director, Professor of Surgery
Fetal Surgeon Chief, Division of Fetal Medicine and Surgery Director of the Maternal Fetal Care Center Director of the Perinatal Surgery Fellowship Professor of Surgery, Boston Children’s Hospital Harvard Medical School
Boston, Massachusetts, United States

Objective: To evaluate and compare rates of hemorrhage and the CDC-defined severe maternal morbidity (SMM) associated with persistent low-lying placenta (LLP) and placenta previa (PP) using a national database.

Study Design: We conducted a retrospective analysis using the Nationwide Readmissions Database (NRD) from 2017 through 2019, reflecting the initial 3 years of coding for LLP. Patients with multifetal gestation, ectopic/molar pregnancies, and other placental abnormalities were excluded. Hemorrhage was defined as ante-, intra-, and post-partum hemorrhage. Baseline characteristics and maternal outcomes were compared using chi-square tests for categorical variables and Kruskal-Wallis tests for continuous variables. Multivariable regression analysis was used to evaluate the risk ratios (RR) of adverse outcomes across these groups.

Results: Among 5,644,185 singleton deliveries, 11,755 were diagnosed with LLP & 23,817 with PP. Compared to normal placentation, LLP was associated with a higher prevalence of hemorrhage (21.1% vs. 4.1%, p < 0.001), and increased RR of hemorrhage (RR: 5.19; 95% CI: 5.01-5.38), SMM (RR: 2.55, 95% CI: 2.35-2.78), blood transfusion (RR: 3.08; 95% CI: 2.79-3.40), and hysterectomy (RR: 4.69; 95% CI: 2.95-7.45). Additionally, delivery admission with LLP was found to have a longer inpatient stay (3 vs. 2 days, p < 0.001) and a higher cost ($21,451 vs. $17,025; p < 0.001). Patients with PP had significantly worse outcomes than those with normal placentation as well, with a 5.28-fold RR of SMM, 7.11-fold RR of blood transfusion, and 10.49-fold RR of hemorrhage.

Conclusion: With the institution of distinct coding for LLP in 2017, we were able to distinguish between patients with LLP and PP. While patients with PP are known to have poor maternal outcomes, patients with LLP also have an increased risk of hemorrhage, SMM, and prolonged inpatient care relative to normal placentation. These findings should be considered during the prenatal counseling and management of patients with LLP.