Year: 2026 | Month: June | Volume: 16 | Issue: 6 | Pages: 267-281
DOI: https://doi.org/10.52403/ijhsr.20260630
Evaluation and Outcome of Anterior Low-Lying Placenta in Previous Lower Segment Caesarean Section Patients from 11-14 Weeks of Gestation and Subsequent Serial Scans: A Prospective Observational Study from Eastern India
MD Azharul Islam1, Sourav Sarkar2, Ritika Pramanik3, Priyam Roy4, Utpalendu Das5
1,2,3,4,5Department of Radiodiagnosis, ICARE Institute of Medical Sciences and Research and Dr. B.C. Roy Hospital, Haldia 721602, West Bengal, India
Corresponding Author: MD Azharul Islam
ABSTRACT
Background: Anterior low-lying placenta in women with a prior lower segment caesarean section (LSCS) is a high-risk obstetric condition predisposing to placenta accreta spectrum (PAS) disorder, antepartum haemorrhage, and peripartum mortality. Serial ultrasonography commencing at 11–14 weeks of gestation has been proposed as an early risk-stratification tool for this patient population; however, prospective evidence from resource-limited settings in South Asia remains limited.
Methods: A prospective observational cohort study was conducted at ICARE Institute of Medical Sciences and Research and Dr. B.C. Roy Hospital, Haldia, West Bengal, India, from October 2024 to June 2025. One hundred consecutive pregnant women with a prior LSCS and anteriorly implanted low-lying placenta confirmed at first-trimester ultrasonography were enrolled. Serial transabdominal and transvaginal scans were performed using a GE Voluson P8 ultrasound machine at 11–14 weeks, 18–22 weeks (anomaly scan), and 28 weeks of gestation. The distance from the lower placental margin to the internal cervical os was measured at each scan. The primary outcome was maternal mortality; secondary outcomes included fetal mortality, perioperative blood loss, morbidly adherent placenta, and mode of delivery. Chi-square, Fisher's exact, and independent-samples t-tests were applied using SPSS v27.0; p ≤ 0.05 was considered statistically significant.
Results: The mean maternal age was 25.90 ± 4.15 years (range 20–35 years); 99% had one prior LSCS. The mean placental distance from the internal os showed minimal change across serial scans: 3.76 ± 0.65 cm at 11–14 weeks, 3.64 ± 0.62 cm at the anomaly scan, and 3.67 ± 0.66 cm at 28 weeks, indicating markedly restricted placental migration. All 100 patients (100%) delivered by LSCS at a mean gestational age of 36.60 ± 0.80 weeks. Maternal mortality occurred in 3% (n = 3) and fetal mortality in 1% (n = 1). Universal perioperative blood loss was documented across the cohort. Statistically significant predictors of maternal mortality (Fisher's exact p = 0.030 for each, except history of antepartum haemorrhage, p = 0.0006) included: multiple prior LSCS, retroplacental haemorrhage at the first-trimester scan, placenta covering the internal cervical os at 28 weeks, morbidly adherent placenta at 28 weeks, antepartum haemorrhage, morbidly adherent placenta confirmed at delivery, and fetal mortality. Mean placental distance at 28 weeks was significantly lower in the maternal mortality group (2.77 ± 0.64 cm) compared with survivors (3.70 ± 0.64 cm; p = 0.015).
Conclusion: Anterior low-lying placenta overlying a prior caesarean uterine scar exhibits markedly restricted migration and carries substantial risk of haemorrhagic morbidity and mortality. A smaller placental distance from the internal os at 28 weeks and retroplacental haemorrhage at the first-trimester scan are significant predictors of adverse maternal outcome. These findings support integration of targeted 11-14-week placental surveillance into routine antenatal care for all women with a prior caesarean delivery.
Key words: Anterior low-lying placenta; placenta accreta spectrum; lower segment caesarean section; first-trimester ultrasonography; placental migration; maternal mortality; antepartum haemorrhage