Background: The avoidance of menstruation through continuous or extended (greater than 28 days) administration of combination hormonal contraceptives (CHCs) has gained legitimacy through its use in treating endometriosis, dysmenorrhea, and menstruation-associated symptoms. Avoidance of menstruation through extended or continuous use of CHCs for reasons of personal preference may have additional advantages to women, including improved compliance, greater satisfaction, fewer menstrual symptoms, and less menstruation-related absenteeism from work or school.
Objectives: To determine the differences between continuous or extended-cycle CHCs (pills, patch, ring) in regimens of greater than 28 days of active hormone compared with traditional cyclic dosing (21 days of active hormone and 7 days of placebo, or 24 days of active hormones and 4 days of placebo). Our hypothesis was that continuous or extended-cycle CHCs have equivalent efficacy and safety but improved bleeding profiles, amenorrhea rates, adherence, continuation, participant satisfaction, and menstrual symptoms compared with standard cyclic CHCs.
Search methods: We searched computerized databases (Cochrane Central Register of Controlled Trials, PUBMED, EMBASE, POPLINE, LILACS) for trials using continuous or extended CHCs (oral contraceptives, contraceptive ring and patch) during the years 1966 to 2013. We also searched the references in review articles and publications identified for inclusion in the protocol. Investigators were contacted regarding additional references.
Selection criteria: All randomized controlled trials in any language comparing continuous or extended-cycle (greater than 28 days of active hormones) versus traditional cyclic administration (21 days of active hormones and 7 days of placebo, or 24 days of active hormones and 4 days of placebo) of CHCs for contraception.
Data collection and analysis: Titles and abstracts identified from the literature searches were assessed for potential inclusion. Data were extracted onto data collection forms and then entered into RevMan 5. Peto odds ratios with 95% confidence intervals were calculated for all outcomes for dichotomous outcomes. Weighted mean difference was calculated for continuous outcomes. The trials were critically appraised by examining the following factors: study design, blinding, randomization method, group allocation concealment, exclusions after randomization, loss to follow-up, and early discontinuation. Because the included trials did not have a standard treatment (type of CHC formulation, route of delivery, or time length for continuous dosing), we could not aggregate data into meta-analysis.
Main results: Twelve randomized controlled trials met our inclusion criteria. Study findings were similar between 28-day and extended or continuous regimens in regard to contraceptive efficacy (i.e., pregnancy rates) and safety profiles. When compliance was reported, no difference between 28-day and extended or continuous cycles was found. Participants reported high satisfaction with both dosing regimens, but this was not an outcome universally studied. Overall discontinuation and discontinuation for bleeding problems were not uniformly higher in either group. The studies that reported menstrual symptoms found that the extended or continuous group fared better in terms of headaches, genital irritation, tiredness, bloating, and menstrual pain. Eleven out of the twelve studies found that bleeding patterns were either equivalent between groups or improved with extended or continuous cycles over time. Endometrial lining assessments by ultrasound and/or endometrial biopsy were done in some participants and were all normal after cyclic or extended CHC use.
Authors' conclusions: The 2014 update yielded four additional trials but unchanged conclusions. Evidence from existing randomized control trials comparing continuous or extended-cycle CHCs (greater than 28 days of active combined hormones) to traditional cyclic dosing (21 days of active hormone and 7 days of placebo, or 24 days of active hormone and 4 days of placebo) is of good quality. However, the variations in type of hormones and time length for extended-cycle dosing make a formal meta-analysis impossible. Future studies should choose a previously described type of CHC and dosing regimen. More attention needs to be directed towards participant satisfaction, continuation, and menstruation-associated symptoms.