HCG Level Decline After D&C at 8 Weeks
After a D&C procedure at 8 weeks gestation, HCG levels typically decline rapidly, with a 70% decrease by day 3 and over 90% decrease by day 5 post-procedure. 1
Normal HCG Clearance Pattern
- HCG follows a predictable decline after uterine evacuation procedures such as D&C 1, 2
- The initial decline is rapid, with a half-life of approximately 0.63 days in the first 2 days following the procedure 2
- By day 3 post-procedure, expect approximately a 70% (±10.6%) decrease from the initial HCG level 1
- By day 5 post-procedure, expect approximately a 91.4% (±4.4%) decrease from the initial HCG level 1
- By days 7-9, HCG levels typically decline by 97.1% (±1.7%) from the initial value 1
- A complete return to non-pregnant levels (undetectable HCG) typically occurs within 2 weeks after the procedure for most women 2
Monitoring Recommendations
- For normal pregnancies terminated by D&C, a single HCG test 2 weeks after the procedure should be sufficient to confirm complete evacuation 2
- If the urine pregnancy test remains positive 4 weeks after the procedure, this may indicate incomplete evacuation or persistent trophoblastic tissue 2
Special Considerations for Molar Pregnancies
- If the D&C was performed for a hydatidiform mole, more intensive HCG monitoring is required 3, 4
- For partial hydatidiform moles, weekly HCG measurements are recommended until there are two consecutive undetectable values 4
- For complete hydatidiform moles, weekly HCG measurements until normalization followed by monthly monitoring for 6 months is recommended 3, 4
- Plateauing or rising HCG levels after molar pregnancy treatment suggests development of gestational trophoblastic neoplasia (GTN) and requires immediate evaluation 3
Factors That May Affect HCG Decline
- The rate of HCG decline is generally not affected by the initial HCG level or gestational duration 1
- Later implantation pregnancies (those that implanted after day 10 of the luteal phase) may show a slightly slower rate of HCG decline 5
- The presence of retained products of conception can slow the decline of HCG levels 2
Warning Signs Requiring Further Evaluation
- If HCG levels plateau (less than 10% fall over three consecutive measurements) or begin to rise after initial decline, this may indicate incomplete evacuation or persistent trophoblastic disease 3, 6
- A positive pregnancy test 4 weeks after D&C warrants further investigation for retained products of conception or persistent trophoblastic tissue 2
- If HCG remains detectable for longer than 6 months after D&C for molar pregnancy, this meets the definition of persistent trophoblastic disease and requires oncologic referral 4
Practical Guidance
- For women who need confirmation of complete evacuation sooner than 1 week after the procedure, a single repeat HCG on day 5 may be clinically useful 1
- A urine pregnancy test with a sensitivity of 1 IU/ml will typically be negative within 2 weeks after a complete evacuation 2
- Safe contraception should be used during the HCG monitoring period, especially after molar pregnancy 4