Keywords
placental migration
ultrasound
second trimester
third trimester
resolution rate
prospective study
How to Cite
Abstract
Background: Placenta previa, a condition where the placenta partially or completely covers the internal cervical os, poses significant maternal and fetal risks during pregnancy. Although frequently diagnosed in the second trimester through routine ultrasonography, many cases resolve spontaneously as pregnancy progresses due to placental migration. Understanding the resolution pattern is essential to avoid unnecessary interventions and optimize perinatal outcomes.
Objective: To evaluate the rate and pattern of resolution of placenta previa diagnosed during the second trimester through follow-up ultrasound assessments in the third trimester.
Methods: This prospective observational study included 146 pregnant women who underwent ultrasound examinations at 16–24 weeks (second trimester) and again after 30 weeks (third trimester). Grades of placenta previa were classified from Grade 0 (normal) to Grade 4 (complete previa). Patients with diabetes, previous placenta previa, or cesarean section were excluded. Data were analyzed using SPSS version 24.0, with descriptive statistics used to assess resolution patterns.
Results: Of the 146 participants, 100 cases (68.4%) of placenta previa resolved spontaneously by the third trimester. There was a marked decline in the number of Grade 1, 2, and 3 cases, while the incidence of Grade 0 (normal placental location) increased to 69.2%, indicating successful placental migration. Conversely, 46 cases (31.5%) remained unresolved, with 25 patients (17.1%) progressing to Grade 4 previa, reflecting either persistence or worsening of the condition. These findings underscore a high rate of natural resolution, while emphasizing the continued need for third-trimester surveillance to identify cases requiring intervention.
Conclusion: A majority of placenta previa cases diagnosed in mid-pregnancy resolve spontaneously by the third trimester. These findings support conservative management with scheduled follow-up ultrasounds to distinguish cases that require intervention. Persistent or progressing cases, particularly those developing into Grade 4, highlight the importance of ongoing surveillance in high-risk patients.