What is the management for a threatened abortion?

Management of Threatened Abortion

The management of threatened abortion should include transvaginal ultrasonography as the diagnostic method of choice to confirm fetal viability and detect subchorionic hematoma, followed by appropriate supportive care and monitoring. 1

Definition and Diagnosis

• Threatened abortion is defined as vaginal bleeding with a closed cervix and viable fetus during the first half of pregnancy 2
• Diagnostic approach should include:
  • Transvaginal ultrasonography to confirm fetal viability and rule out ectopic pregnancy 1
  • Assessment for presence and size of subchorionic hematoma, which is found in approximately 43% of threatened abortion cases 3
  • Evaluation of Rh status in all cases 1, 2

Initial Management

• Bed rest is recommended until 48 hours after cessation of bleeding, as studies suggest it may reduce spontaneous abortion rates (9.9% vs 23.3% in non-bed rest groups) and increase rates of term pregnancy (89% vs 70%) 3, 4
• Supportive care should include:
  • Folic acid supplementation 3
  • Uterine sedatives to reduce cramping 3
  • Hormonal treatment (progesterone) may be considered until 28 weeks gestation, as progesterone is critical for early pregnancy maintenance 5, 3

Rh Status Management

• For Rh-negative women with threatened abortion and viable fetus, there is no evidence-based recommendation for anti-D immunoglobulin administration, and many physicians do not administer it when there is a live embryo or fetus 1
• However, in cases of documented first-trimester loss of established pregnancy, administer 50 μg of anti-D immunoglobulin to Rh-negative women 1, 2

Follow-up Care

• Serial ultrasound examinations should be performed to assess fetal growth and development 1
• Monitor for potential complications that occur more frequently after threatened abortion:
  • Preterm labor (25.2% vs 9.4% in pregnancies without threatened abortion) 6
  • Premature rupture of membranes (10.2% vs 4.8%) 6
  • Placental abruption (4% vs 1.4%) 6
  • Intrauterine growth restriction (13.2% of continued pregnancies after threatened abortion) 3

Prognosis

• Approximately 75-80% of threatened abortions will continue to term with appropriate management 3
• Risk factors for poor outcomes include:
  • Larger subchorionic hematomas (>20 cm²) are associated with higher rates of spontaneous abortion 3
  • Multiple episodes of bleeding increase risk of spontaneous preterm delivery and placental abruption 6
  • Greater amount of bleeding correlates with increased risk of placental abruption 6

Important Considerations

• Avoid misdiagnosis of incomplete abortion, which requires careful ultrasound evaluation to differentiate from ectopic pregnancy 2
• Recognize that neonatal weight tends to be lower in pregnancies complicated by threatened abortion, even in term deliveries (3046g vs 3317g) 6
• Be aware of psychological impact, as women may experience significant depression and anxiety for up to one year after spontaneous abortion 7