hCG trend after medication abortion: A prospective phyisologic study
Awarded 2014
Complex Family Planning Fellowship Research
Katherine Pocius, MD
Planned Parenthood League of Massachusetts

Background: Medication abortion accounts for more than a third of abortions in the US prior to nine weeks gestation. It is very effective, with ongoing pregnancies occurring in less than 1% of cases. Patients must return to the clinic to confirm that the procedure was complete because symptoms alone are not very accurate in identifying ongoing pregnancies. Routinely, ultrasound or blood hormone levels are used to determine that the abortion procedure is complete. Blood work compares the level of serum hCG (pregnancy hormone) prior to the medical abortion to the serum hCG level 7-14 days after the abortion procedure; an 80% decrease is considered to be consistent with a successful medical abortion.
Although serum hCG monitoring is an increasingly common method of confirming successful medical abortion, there is limited information about typical hCG trends in the first few days following the procedure. My recent study represents the largest of only four studies that examine hCG values collected before Day 7, and is limited by the fact that it was conducted as a retrospective chart review. This means that it was not possible to obtain precise information about the timing of medication administration or expulsion of the pregnancy, and hCG values ranged widely. Additionally, the study looked only at very early pregnancies where the ultrasound showed no yolk sac, so the results may not be generalizable to other patients.
Statement of purpose: The purpose of this study was to recruit women who were seeking medical abortion and collect hCG data from them in the first 7 days after they initiated medical abortion, in order to describe normal hCG trends in the first few days following the procedure.
Methodology: This study recruited healthy women with pregnancies up to 63 days gestation who were eligible for medication abortion at Planned Parenthood League of Massachusetts’ Boston clinic. Half of the study population had a gestational age of over seven weeks, and the other half had a gestational age of seven weeks or less. Patients followed Planned Parenthood’s standard clinic procedure for their ultrasound and their medical abortion (although study subjects had a slightly smaller time-window in which to take their misoprostol). Patients’ hCG levels were collected on the day they presented for their medication abortion (Day 1), and again during clinic visits on Day 3, Day 5, and sometime between Day 7 and Day 14. Patients also self-administered a semi-quantitative urine hCG test at each visit.
Important findings: Of the fifty-nine study subjects who completed the study according to our protocol, fifty-seven of them (97%) had a complete medication abortion that required no additional medical treatment. For those study subjects, serum hCG levels declined by a mean of 70.0% at Day 3, 91.5% at Day 5, and 98.2% at their final study visit between Day 7 and Day 14. There was no difference in the hCG decline based on gestational age at time of medication abortion, or based on initial hCG levels.
Conclusion/summary statement about relevance: The decline in hCG levels in the first few days following medication abortion is rapid and predictable as early as Day 5. A decrease of 87% or more on Day 7-12 can be considered successful. This decline doesn’t depend on initial hCG level or gestational age.