Anembryonic Pregnancy

Anembryonic pregnancy is a gestational sac that develops without an embryo, once called blighted ovum. It results from early failure of the embryo, usually from chromosomal abnormality. It matters because the sac can persist with pregnancy symptoms and a positive test, and diagnosis needs strict scan criteria.

• Risk factors: maternal age above 35 years, previous miscarriage, smoking.
• The sac grows for a short time, then stops.
• Found at 7 to 12 weeks, often on a routine scan.

Women have a missed period, positive test and sometimes pregnancy symptoms, with brown spotting or none. Examination shows a closed os and uterus smaller than dates.

• Pain and bleeding may be mild.
• Pregnancy symptoms may persist because hCG remains positive for some time.
• Differential diagnosis: early normal pregnancy with wrong dates, ectopic pregnancy with pseudosac, molar pregnancy, embryonic demise.
• Complications: miscarriage, haemorrhage, infection, retained products, anxiety.

The diagnosis is made on transvaginal ultrasound.

• Mean sac diameter 25 mm or more with no embryo confirms the diagnosis.
• A sac of 16 to 24 mm with no embryo needs a repeat scan after 7 to 14 days.
• Haemoglobin, blood group and Rhesus status; hCG levels plateau or rise slowly.
• Histology of tissue to exclude molar change.

The principle is to offer expectant, medical or surgical evacuation once the diagnosis is confirmed.

• Supportive: counselling; analgesia; written advice on bleeding; expectant care for up to 14 days if stable.
• Pharmacological: misoprostol 800 micrograms vaginally, repeat once after 3 hours if no bleeding, and repeat the full course after 24 hours if the sac persists; mifepristone 200 mg oral followed 24 to 48 hours later by misoprostol 800 micrograms vaginally where available; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); ibuprofen 400 mg oral 8-hourly with food for 3 days.
• Procedures: manual vacuum aspiration up to 12 weeks size with paracervical block (lignocaine 1 percent, 20 mL) if the patient chooses surgery or bleeding is heavy.
• Special groups: Rhesus negative women give anti-D immunoglobulin 250 IU IM within 72 hours of evacuation.
• Red flags: heavy bleeding, fever above 38 degrees Celsius, severe pain, offensive discharge.
• Follow-up: urine pregnancy test at 3 weeks; contraception; review histology; investigation after 3 consecutive losses.