Regarding the classification, clinical presentation, and complications of placenta previa, all of the following statements are correct EXCEPT:

Explanation

## Placenta Previa: Classification, Presentation, and Outcomes ### Classification System **Key Point:** Placenta previa is classified based on the relationship of the lower placental edge to the internal cervical os: | Type | Definition | Vaginal Delivery | |---|---|---| | **Complete (Total)** | Placenta completely covers the internal os | Contraindicated | | **Partial** | Placenta partially covers the internal os | Contraindicated | | **Marginal** | Lower edge is within 2 cm of the internal os | May be attempted if >2 cm clearance | | **Low-lying** | Placenta within 2 cm but not overlapping the os | Vaginal delivery usually safe | ### Clinical Presentation **High-Yield:** Placenta previa typically presents with: - Painless vaginal bleeding (cardinal feature) - Usually after 20 weeks gestation - May be triggered by intercourse, vaginal examination, or spontaneously - Bleeding can range from spotting to massive hemorrhage ### Maternal Outcomes **Clinical Pearl:** Maternal mortality from placenta previa is indeed rare in developed countries (<1%) due to: - Availability of blood products and transfusion - Access to cesarean delivery - Hospitalization and monitoring - However, in resource-limited settings, maternal mortality remains significant ### Perinatal Outcomes and Morbidity **Warning:** The primary causes of increased perinatal mortality in placenta previa are NOT hemorrhage alone, but rather: 1. **Preterm birth** — most common complication - Occurs in 20-30% of cases - Due to recurrent bleeding episodes necessitating early delivery - Iatrogenic prematurity from indicated early delivery 2. **Intrauterine growth restriction (IUGR)** — occurs in 10-15% of cases - Due to reduced placental surface area and abnormal placentation - Associated with abnormally invasive placenta 3. **Fetal anemia and hypoxia** — from chronic blood loss 4. **Malpresentation** — breech presentation more common due to placental location **Key Point:** Perinatal mortality is elevated primarily due to prematurity and IUGR, NOT because of fetal hemorrhage from the previa itself. The fetus does not bleed in uncomplicated placenta previa—the bleeding is maternal. ### Risk Factors for Severe Bleeding - Complete previa (vs. marginal) - Anterior placental location - Multiparity - Maternal age >35 years [cite:Williams Obstetrics 26e Ch 34]