title: Rationale for eliminating the hormone-free interval in modern oral contraceptives.
abstract: BACKGROUND
  Although most low-dose combined oral contraceptives (COCs) include 7-day hormone-free intervals (HFIs), these COCs could incompletely suppress ovarian activity.
  
  
  OBJECTIVE
  To review the impact of HFIs on ovarian suppression and tolerability, and evaluate the utility of COCs without traditional 7-day HFIs.
  
  
  METHODS
  PubMed was searched for clinical studies published in English between January 1980 and April 2015 on the impact of HFIs and HFI modifications in COCs.
  
  
  METHODS
  Articles assessing contraceptive efficacy or tolerability as the primary focus were included.
  
  
  METHODS
  Abstracts of 319 articles were screened.
  
  
  RESULTS
  Analysis of the 161 articles selected revealed that suppression of ovarian activity with low-dose COCs with 7-day HFIs is suboptimal. Loss of ovarian suppression during 7-day HFIs is commonly associated with follicular development, and most dominant follicles appear during this period. By contrast, increased ovarian suppression was noted in regimens that shortened or eliminated the HFI, or that substituted low-dose ethinyl estradiol for the HFI.
  
  
  CONCLUSIONS
  Extended regimens with modified HFIs may provide greater ovarian suppression with the potential for increased contraceptive effectiveness. Additional research is needed to evaluate whether COC regimens that include 10μg ethinyl estradiol instead of an HFI may improve tolerability.
authors.affiliation: John Hopkins School of Medicine, Baltimore, MD, USA; The Maryland Center for Sexual Health, Lutherville, MD, USA. Electronic address: alondon@comcast.net.
authors.forename: Andrew
authors.initials: A
authors.lastname: London
authors.affiliation: Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Jensen
mesh_terms: D003277:Contraceptives, Oral, Combined / Q000008:administration & dosage* / Q000009:adverse effects; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage* / Q000009:adverse effects; D017135:Desogestrel / Q000008:administration & dosage; D004967:Estrogens / Q000008:administration & dosage* / Q000009:adverse effects; D004997:Ethinyl Estradiol / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors; D006801:Humans; D007986:Luteinizing Hormone / Q000037:antagonists & inhibitors; D006080:Ovarian Follicle / Q000187:drug effects*
chemical_list: D003277:Contraceptives, Oral, Combined; D003278:Contraceptives, Oral, Hormonal; D004967:Estrogens; D004997:Ethinyl Estradiol; D017135:Desogestrel; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: Combined oral contraceptives; Extended regimen; Hormonal contraception; Hormone-free interval; Menstrual suppression; Unscheduled bleeding; Withdrawal bleeding