From the Guidelines
Expectant management of placenta previa is recommended for women who are asymptomatic and have a placenta previa diagnosis before 32 weeks of gestation, with regular follow-up ultrasounds to monitor placental position and fetal growth, as suggested by the Society for Maternal-Fetal Medicine recommendations 1.
Key Components of Expectant Management
- Women with placenta previa should be advised to avoid heavy lifting, strenuous activities, and sexual intercourse to minimize the risk of bleeding.
- For women with a history of bleeding, hospitalization is recommended until 36 weeks of gestation or until delivery, whichever comes first, to closely monitor their condition and prevent complications.
- Corticosteroids, such as betamethasone 12 mg intramuscularly, may be administered to promote fetal lung maturity if preterm delivery is anticipated.
- Women with placenta previa should also receive iron supplements, such as ferrous sulfate 325 mg orally three times a day, and folate 1 mg orally daily to prevent anemia.
- Regular ultrasound assessments should be performed every 2-4 weeks to monitor placental position and fetal growth, as well as to assess for interval change and possible progression of the depth of invasion 1.
- In cases where bleeding occurs, immediate medical attention is required, and delivery may be necessary.
- Tocolytic agents, such as nifedipine 10-20 mg orally every 4-6 hours, may be used to temporarily delay delivery in cases of preterm labor, but this should be done with caution and close monitoring.
- Women diagnosed with placenta previa after 28 weeks’ gestation are at risk for spontaneous labour and should avoid moderate-to-vigorous physical activity (MVPA), but maintain their activities of daily living and low-intensity activity (ie, walking) 1. Ultimately, the decision to continue expectant management or proceed with delivery should be individualized based on the woman's specific clinical situation and gestational age.
From the Research
Expectant Management of Placenta Previa
The expectant management of placenta previa involves several key components, including:
- Avoidance of digital vaginal examination 2
- Delay of delivery until 36 weeks' gestation and/or documented fetal lung maturity 2
- Transfusion support to maintain maternal hematocrit greater than or equal to 30% 2
- Serial ultrasonography 3, 4, 2, 5
- Antepartum fetal heart rate monitoring 2
- Glucocorticoids 3, 4
- Tocolytic therapy 6
- Elective delivery by cesarean section 3, 4, 2, 5
Tocolytic Therapy
Tocolytic therapy has been shown to be effective in prolonging pregnancy and increasing birth weight in cases of symptomatic placenta previa 6. The use of tocolysis has been associated with a clinically significant delay of preterm delivery, with a significant improvement in clinical parameters such as interval from admission to delivery and birth weight 6.
Ultrasound Evaluation
Ultrasound evaluation plays a crucial role in the diagnosis and management of placenta previa, including:
- Diagnosis of placenta previa 3, 4, 2, 5
- Serial placental localization to determine the timing, route, and place of delivery 4
- Prediction of placental migration 5
- Diagnosis of vasa previa and placenta accreta 5
Outpatient Management
Outpatient management of placenta previa may be an acceptable alternative to traditional conservative expectant inpatient management for selected patients, with a significant reduction in maternal hospital days and costs 3. However, patients with recurrent bleeding or other complications may require readmission for evaluation and treatment.