Working a few Peds shifts lately I’ve run into the same question: when should your urine pregnancy test (or quantitative serum hCG) be negative after a regular pregnancy, a termination, or a miscarriage (meaning, could she really already be pregnant again)? I hear different answers depending on the obstetrical consultant I ask, so I decided to do a little literature search myself. It’s really only been looked at in very small studies; I’ve got the specific numbers if you want them, but based on the studies I found, it looks something like this:
After a Full-Term Pregnancy:
- Should be 3 weeks or less. In some women, ovulation may occur as early as 3 weeks after delivery.
After a Termination with Misoprostol/Mifepristone:
- In one study, following up at 6-18 days, if the hCG level was 80% lower than the initial hCG level, there was a positive predictive value for successful expulsion of 0.995. There was no information on when the level dropped to 0 or <5.
After a D&C Termination:
- Depends on the initial hCG, but mean time was 35 days, but could be up to 60 days.
After Miscarriage in Women Who Then Had a D&E for Continued Bleeding:
- Median ~20 days, range 9-22 days.
After Ectopic with Laparotomy:
- Ectopics had the lowest hCG to begin with, reached 0 by 1-31 days, median 8.5 days.
- Routine terminations of pregnancy—should we screen forgestational trophoblastic neoplasia? The Lancet, 2004.
- Human chorionic gonadotropin in maternal plasma after induced abortion, spontaneous abortion, and removed ectopic pregnancy. Obstetrics and Gynecology, 1984.
- Verifying the effectiveness of medical abortion; ultrasound versus hCG testing. European Journal of Obstetrics and Gynecology, 2003.