Approximately 20-30% of pregnancies are classified as high-risk due to factors such as maternal age, pre-existing medical conditions, obstetric complications, or multiple gestations. This proportion reflects a balance where significant monitoring and potential interventions are necessary to optimize maternal and fetal outcomes. Identifying high-risk pregnancies allows for appropriate specialized care and timely surgical interventions when complications such as preeclampsia, placenta previa, or fetal distress arise, which improves prognosis. Therefore, this classification is crucial for guiding clinical decision-making and resource allocation in obstetrics.

Reference: Williams Obstetrics, Cunningham FG, 25th Edition.