What is the diagnosis and treatment for a blighted ovum?

Blighted Ovum: Diagnosis and Management

A blighted ovum, also known as an anembryonic pregnancy, is a type of early pregnancy loss where a gestational sac develops without an embryo, requiring either expectant, medical, or surgical management based on patient preference and clinical circumstances. 1

Diagnosis

Ultrasound Criteria

• Definitive diagnosis requires one of the following ultrasound findings 1:
  • Mean sac diameter (MSD) ≥25 mm with no embryo
  • Absence of embryo with cardiac activity ≥14 days after visualization of gestational sac with no yolk sac

Concerning Findings (Require Follow-up)

• Mean sac diameter 16-24 mm with no embryo
• Absence of embryo with cardiac activity 7-13 days after visualizing gestational sac with no yolk sac 1

Expected Timeline of Normal Early Pregnancy

• Gestational sac: visible at 4.5-5 weeks gestation (MSD 2-3 mm)
• Yolk sac: visible when gestational sac >8 mm
• Cardiac activity: should be present by 6 weeks gestation 1

Diagnostic Approach

1. Transvaginal ultrasound is the gold standard for diagnosis
2. When findings are equivocal, follow-up ultrasound in 7-14 days is essential
3. hCG levels may be helpful (discriminatory level ~3000 mIU/mL) 1

Management Options

1. Expectant Management

• Allows natural expulsion of pregnancy tissue
• Success rates: 65-80% within 2-4 weeks
• Appropriate for hemodynamically stable patients without signs of infection 1

2. Medical Management

• Medication: Misoprostol 400 mcg intravaginally
• Efficacy: Significantly more effective than placebo (63% vs 18.5% complete abortion rate) 2
• Side effects: Lower abdominal pain (74.1%) and fever (14.8%) are common 2
• Consider when patient prefers not to wait for spontaneous abortion 1

3. Surgical Management

• Procedure: Suction dilation and curettage (D&C) under ultrasound guidance
• Indications:
  • Patient preference for immediate resolution
  • Excessive bleeding
  • Signs of infection
  • Significant emotional distress with expectant management 1
• Should be performed under ultrasound guidance to reduce risk of uterine perforation 3

Management Algorithm

1. Confirm diagnosis with appropriate ultrasound criteria
2. Assess patient stability (hemodynamic status, bleeding, infection)
3. Discuss management options with patient
4. Select approach based on:
   • Patient preference
   • Clinical circumstances (bleeding, infection)
   • Access to follow-up care

Important Considerations

Pitfalls to Avoid

• Premature diagnosis without meeting established criteria
• Immediate intervention before confirming diagnosis with follow-up ultrasound 1
• Failure to recognize multiple gestations where one sac may be normal and the other blighted 4, 5

Follow-up

• For expectant or medical management, follow-up ultrasound is needed to confirm complete expulsion
• Monitor hCG levels until they return to normal
• Provide emotional support as early pregnancy loss can cause significant distress

Special Scenarios

• In multiple gestations, one sac may be blighted while the other develops normally 4, 5
• Heterotopic pregnancies (simultaneous intrauterine and ectopic pregnancies) are rare but possible, even when the intrauterine pregnancy is a blighted ovum 6

Remember that a blighted ovum is a form of early pregnancy loss that requires sensitive management and appropriate follow-up to ensure complete resolution and support the patient's emotional wellbeing.