A pilot study on the use of a 7-day course of letrozole followed by misoprostol for the termination of early pregnancy up to 63 days.
BACKGROUND
Our previous randomized controlled study showed that the complete abortion rate in termination of pregnancy up to 63 days with the combined use of letrozole for 3 days followed by vaginal misoprostol was significantly higher than that of misoprostol alone. A positive correlation was observed between the basal estradiol level and the failure rate. We performed this pilot study to assess if a longer course of letrozole followed by misoprostol would improve the estradiol suppression and the complete abortion rate of pregnancy up to 63 days.


METHODS
Twenty subjects requesting legal termination of pregnancies up to 63 days were recruited. Medical abortion was offered with letrozole 10 mg daily for 7 days followed by vaginal misoprostol 800 mcg on the 7th day.


RESULTS
Median induction-to-abortion interval was 7.5 h (range, 4.75-10.75 h). Overall complete abortion rate was 95%. All subjects with gestation ≤49 days (12/12) as well as 87.5% of subjects with gestation between 50 and 63 days (7/8) had complete abortion. No major adverse event were reported and over 88% of women would like to have medical termination as an option should it be required in the future.


CONCLUSIONS
This pilot study showed that a 7-day course of letrozole followed by vaginal misoprostol was associated with a very high complete abortion rate (95%) which is comparable to the standard regimen with sequential use of mifepristone and misoprostol in medical termination of early pregnancy up to 63 days.
Department of Obstetrics and Gynaecology, the University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China. twyyeung@hku.hk
Tracy Wing Yee
TW
Yeung
Vivian Chi Yan
VC
Lee
Ernest Hung Yu
EH
Ng
Pak Chung
PC
Ho
D000020:Abortifacient Agents, Nonsteroidal / Q000008:administration & dosage* / Q000009:adverse effects; D000028:Abortion, Induced / Q000009:adverse effects; D000328:Adult; D047072:Aromatase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004334:Drug Administration Schedule; D004958:Estradiol / Q000097:blood; D004965:Estrogen Antagonists / Q000008:administration & dosage / Q000009:adverse effects; D020847:Estrogen Receptor Modulators / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D006723:Hong Kong; D006801:Humans; D000077289:Letrozole; D016595:Misoprostol / Q000008:administration & dosage* / Q000009:adverse effects; D009570:Nitriles / Q000008:administration & dosage* / Q000009:adverse effects; D017060:Patient Satisfaction; D010865:Pilot Projects; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011275:Pregnancy, Unwanted / Q000097:blood; D014230:Triazoles / Q000008:administration & dosage* / Q000009:adverse effects; D055815:Young Adult
D000020:Abortifacient Agents, Nonsteroidal; D047072:Aromatase Inhibitors; D018997:Chorionic Gonadotropin, beta Subunit, Human; D004965:Estrogen Antagonists; D020847:Estrogen Receptor Modulators; D009570:Nitriles; D014230:Triazoles; D016595:Misoprostol; D004958:Estradiol; D000077289:Letrozole