Aim This review summarises the available data on the disadvantages of the 7-day contraceptive-free interval (CFI) of combined oral contraceptives (COCs), in contrast to shorter CFIs or continuous use – including flexible regimens – and provides recommendations for practice.
Methods Relevant papers were identified by Medline and PubMed. The final reference list was generated on the basis of relevance to the review, with priority given to systematic reviews and randomised controlled trials.
Results There is considerable inter- and intra-individual variation in the absorption and metabolism of COCs. Even with perfect use, the loss of endocrine suppression during the standard 7-day CFI allows follicular development with the risk of escape ovulation in a vulnerable minority. This risk increases in typical users whenever the CFI is prolonged: late restarts are a common reason for pill omissions. Shortening or eliminating the CFI improves contraceptive efficacy using the lowest doses available, without evidence to date of compromised safety.
Conclusions There is no scientific evidence to support a 7-day CFI and it should be replaced either by a continuous flexible regimen, or extended regimens with a shortened CFI, prescribed first-line. In women preferring a monthly ‘bleed’, a 4-day CFI similarly provides a greater safety margin when pills are omitted.
- hormone-free interval
- continuous regimen
- extended regimen
- flexible regimen
- combined oral contraceptives
- hormonal contraception
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Contributors Professor MacGregor undertook the literature search and wrote the first draft. Professor Guillebaud revised the draft and both authors approved the final version. Both authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests Professor MacGregor reports personal fees from Consilient, Bayer and Elsevier, outside the submitted work. Professor Guillebaud reports personal fees from the Wellcome Trust and from Bayer HealthCare, outside the submitted work.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.