Management of Molar Pregnancy
A 25-year-old woman at 9 weeks presents with vaginal spotting and passing vesicles. Uterine size is larger than dates, serum beta-hCG is 410 000 IU/L, and ultrasound shows a snowstorm appearance with no fetus. Blood pressure is 150/96 mm Hg and her blood group is O negative. Which of the following is the most appropriate management?
- A.Vaginal misoprostol induction
- B.Intramuscular methotrexate therapy
- C.Expectant observation with serial scans
- D.Suction evacuation of the uterusCorrect
Explanation
Suction evacuation under ultrasound guidance is the definitive treatment for a hydatidiform mole and should be performed promptly once the diagnosis is made. Suction is preferred over sharp curettage because it minimises uterine perforation and reduces trophoblastic embolisation, and oxytocin is generally started only after evacuation has begun to limit dissemination of trophoblastic tissue. Anti-D immunoglobulin is required in this rhesus-negative woman. Medical induction with prostaglandins is avoided in molar pregnancy because uterine contractions before evacuation may force trophoblast into the venous system and are associated with a higher risk of subsequent gestational trophoblastic neoplasia. Methotrexate is chemotherapy reserved for persistent gestational trophoblastic neoplasia, diagnosed by a plateau or rise in hCG during follow-up, not for primary evacuation. Expectant management leaves a lesion with malignant potential in place and risks ongoing haemorrhage, hyperthyroidism, and early preeclampsia. After evacuation, serial quantitative hCG is measured until three consecutive normal weekly values are obtained and then monthly for 6 months, with reliable contraception throughout so that a new pregnancy does not obscure a rising hCG.
Why each option
- A.
- Prostaglandin induction risks trophoblastic embolisation and dissemination and is not the preferred method of evacuating a mole.
- B.
- Methotrexate treats persistent gestational trophoblastic neoplasia after evacuation, not the initial molar pregnancy.
- C.
- Observation leaves tissue with malignant potential in situ and permits continued bleeding and hormonal complications.
- D.
- Correct. Suction evacuation is the primary treatment, followed by serial hCG monitoring and contraception for 6 months.
Reference: RCOG Green-top Guideline 38: Gestational Trophoblastic Disease, 2020
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