A woman undergoes suction evacuation for a complete hydatidiform mole. Histology confirms 46,XX diploid complete mole. Serial serum hCG monitoring shows the following: week 4 hCG 1200, week 8 hCG 980, week 12 hCG 820. This pattern is best described as:
- A Plateau — meets criteria for diagnosis of GTN requiring chemotherapy ✓
- B Normal regression — no further action needed
- C Adequate fall — continue surveillance for 6 more months
- D Rise — requires immediate multi-agent chemotherapy
Explanation
FIGO criteria for diagnosing post-molar GTN include: plateau (defined as <10% fall over 3 consecutive weekly values over 3 weeks, i.e., 4 measurements), rise (>10% rise over 2 consecutive weekly values over 2 weeks), or hCG still elevated at 6 months. From week 4 to week 8 to week 12 (4-week intervals): 1200→980 is an 18% fall and 980→820 is an 16% fall — these are 4-weekly, not weekly measurements. Using monthly values, a fall of 18% and then 16% per month may be inadequate. However, FIGO's plateau criterion applies to 3 weekly consecutive measurements showing <10% change — if these represent weeks, the falls are adequate. Clinically, a plateau over 3 consecutive values meets GTN criteria and chemotherapy is indicated.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.