Accounting for time: insights from a life-table analysis of the efficacy of medical abortion.
OBJECTIVE
Previously published analyses have ignored the temporal nature of medical abortion and calculated effectiveness as the proportion of abortions that succeed. By using life tables, we incorporate the important element of time to produce unbiased efficacy rates as well as afford insight into the medical abortion process.


METHODS
Using data on 6568 women from 6 previously published mifepristone-misoprostol medical abortion studies, we generated multidecrement life table efficacy curves and evaluated the cumulative probability of successful medical abortion.


RESULTS
Efficacy rates calculated using proportions are biased because of loss to follow-up. Compliance with the medical abortion regimen was high. More than 80% of abortions were complete within a week of receiving mifepristone. Success continued to improve thereafter. Most surgical interventions were unnecessary.


CONCLUSIONS
Follow-up visits can be scheduled within a week of receiving mifepristone; however, aspirations should not be performed routinely if the abortion is not complete.
Hedley
Allison
A
Office of Population Research, Princeton University, Princeton, NJ, USA.
Ellertson
Charlotte
C
Trussell
James
J
Turner
Abigail Norris
AN
Aubény
Elisabeth
E
Coyaji
Kurus
K
Ngoc
Nguyen Thi Nhu
NT
Winikoff
Beverly
B
D000019:Abortifacient Agents / Q000627:therapeutic use*; D000032:Abortion, Therapeutic / Q000379:methods* / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D002986:Clinical Trials as Topic; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007194:India; D008875:Middle Aged; D015735:Mifepristone / Q000627:therapeutic use*; D016595:Misoprostol / Q000627:therapeutic use*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011336:Probability; D018570:Risk Assessment; D013223:Statistics as Topic; D016896:Treatment Outcome
D000019:Abortifacient Agents; D016595:Misoprostol; D015735:Mifepristone