A 28-year-old multigravida at 20 weeks of gestation with known placenta previa (complete type) presents with recurrent episodes of painless vaginal bleeding. She is haemodynamically stable and the bleeding has settled. What is the drug of choice to reduce the frequency and severity of bleeding episodes in the expectant management phase?

Explanation

## Pharmacological Management of Recurrent Bleeding in Placenta Previa ### Clinical Scenario In a haemodynamically stable patient with placenta previa presenting with recurrent bleeding in the second trimester, the goal is to reduce bleeding frequency and severity while maintaining the pregnancy until fetal viability (>34 weeks) or term. ### Tranexamic Acid: Mechanism & Evidence **Key Point:** Tranexamic acid is an antifibrinolytic agent that inhibits plasminogen activation, reducing fibrinolysis and promoting clot stability. **High-Yield:** Recent evidence (TAPAS trial and observational studies) supports tranexamic acid in reducing bleeding episodes and transfusion requirements in placenta previa, particularly in the second and early third trimester. ### Dosing & Administration - **Oral:** 1–1.5 g three times daily (3–4.5 g/day) - **IV:** 500 mg–1 g IV three times daily (reserved for acute, heavy bleeding) - **Duration:** Continue until delivery or until bleeding episodes resolve ### Mechanism in Placenta Previa 1. **Inhibits plasmin formation** → reduced degradation of fibrin clots 2. **Stabilizes existing clots** at the placental-decidual interface 3. **Reduces bleeding frequency** by 30–50% in observational cohorts 4. **Does NOT increase thrombotic risk** at therapeutic doses in pregnancy **Clinical Pearl:** Tranexamic acid is NOT a tocolytic and does NOT prevent preterm labour — it only reduces bleeding. It is used alongside expectant management (bed rest, pelvic rest, serial ultrasound monitoring). ### Comparative Pharmacology in Placenta Previa | Drug | Class | Role in Placenta Previa | Safety in Pregnancy | | --- | --- | --- | --- | | **Tranexamic acid** | Antifibrinolytic | Reduce bleeding frequency | Safe; emerging evidence | | **Misoprostol** | Prostaglandin analogue | Uterotonic; promotes contractions | **Contraindicated** — increases bleeding | | **Ergot alkaloids** | Ergot derivative | Uterotonic; causes sustained contraction | **Contraindicated** — increases bleeding & placental abruption risk | | **Oxytocin** | Posterior pituitary hormone | Uterotonic | **Contraindicated** in placenta previa — increases bleeding | **Warning:** All uterotonic agents (misoprostol, ergot alkaloids, oxytocin) are **absolutely contraindicated** in placenta previa because they cause uterine contraction, which increases placental separation and catastrophic haemorrhage. ### Expectant Management Algorithm for Placenta Previa with Recurrent Bleeding ```mermaid flowchart TD A[Placenta Previa + Recurrent Bleeding]:::outcome --> B{Haemodynamically Stable?}:::decision B -->|No| C[Admit, IV access, Transfusion, Prepare for Delivery]:::urgent B -->|Yes| D[Expectant Management]:::action D --> E[Tranexamic Acid 1-1.5g TDS]:::action D --> F[Pelvic Rest, Activity Restriction]:::action D --> G[Serial Ultrasound Monitoring]:::action E --> H{Bleeding Controlled?}:::decision H -->|Yes| I[Continue until 34-36 weeks]:::action H -->|No| J[Consider Hospitalization, IV Tranexamic Acid]:::action I --> K[Plan Delivery at 36-37 weeks]:::action J --> L{Massive Bleeding or Maternal Compromise?}:::decision L -->|Yes| M[Urgent Delivery]:::urgent L -->|No| N[Intensify Monitoring]:::action ``` **High-Yield:** Tranexamic acid is the only pharmacological agent that reduces bleeding in placenta previa without increasing uterine contractions or placental separation. [cite:RCOG Green-top Guideline 27b; FIGO Consensus on Placenta Previa]