Endometrial microstructure after long-term use of a 91-day extended-cycle oral contraceptive regimen.
OBJECTIVE
To assess the effect on the endometrial microstructure of an extended-cycle oral contraceptive (OC) regimen containing ethinyl estradiol (EE) and levonorgestrel (LNG).


METHODS
Subjects received up to four cycles of a 91-day extended-cycle OC regimen (84 consecutive days of monophasic 30 microg EE/150 microg LNG followed by 7 days of placebo). Endometrial biopsies were performed prior to the initiation and at the completion of therapy. All endometrial samples were processed centrally and reviewed by three independent pathologists blinded to treatment groups.


RESULTS
Endometrial biopsies were performed in 50 women. In general, samples taken after completion of therapy with no further hormonal exposure demonstrated rapid return to normal endometrial cycling. In contrast, the majority of subjects still on active extended hormonal OC therapy at the time of biopsy had inactive or atrophic endometrium. No intravascular blood clots were observed in any of the specimens.


CONCLUSIONS
The endometrial findings observed in this cohort of women treated with a 91-day extended-cycle OC regimen for up to 1 year showed no significant pathology. Additionally, the endometrium reverted quickly to normal cyclic changes in those subjects who, after completing therapy, elected not to continue with hormonal contraception.
Anderson
Freedolph D
FD
The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, VA 23501, USA. fanderson4@cox.net
Hait
Howard
H
Hsiu
Jeng
J
Thompson-Graves
Allison L
AL
Wilborn
Walter H
WH
Williams
Robert F
RF
D000293:Adolescent; D000328:Adult; D001706:Biopsy; D015331:Cohort Studies; D003277:Contraceptives, Oral, Combined / Q000008:administration & dosage*; D003280:Contraceptives, Oral, Synthetic / Q000008:administration & dosage*; D004717:Endometrium / Q000187:drug effects* / Q000648:ultrastructure; D019304:Ethinyl Estradiol-Norgestrel Combination / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D013997:Time Factors
D003277:Contraceptives, Oral, Combined; D003280:Contraceptives, Oral, Synthetic; C482584:Seasonale; D019304:Ethinyl Estradiol-Norgestrel Combination