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Triphasic versus monophasic oral contraceptives for contraceptionGrimes DA, Lopez LM, Schulz KF, Van Vliet HAAM, Helmerhorst FM
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SummaryBirth control pills with three phases versus one phaseSide effects of birth control pills may keep women from using them as planned. Attempts to decrease side effects led to the three-phase pill in the 1980s. Pills with three phases provide different amounts of hormones over three weeks. One-phase pills have the same amount of hormone for three weeks. Whether three-phase pills lead to fewer pregnancies is unknown. Nor is it known if the pills give better cycle control or fewer side effects. This review looked at whether three-phase pills worked as well as one-phase pills. It also studied whether women had fewer side effects with these pills. We did a computer search for studies of pills with three phases versus pills with one phase. We also wrote to researchers and manufacturers to find other trials. We included randomized trials in any language. The studies had to have at least three treatment cycles. We found 21 trials that looked at three-phase versus one-phase birth control pills. Many studies did not have good methods and the authors did not always report all their methods. The two types of pills did not differ in the numbers of women who got pregnant. Some trials found better bleeding patterns with the three-phase pill. The numbers of women who stopped using the pills were about the same for both types of pills. The evidence was not strong enough to say whether the three-phase pill was better than the one-phase pill for pregnancy prevention, bleeding patterns, or continued use. Therefore, we recommend one-phase pills for women starting to use birth control pills. Large trials of good quality are needed to see if pills with three phases work better than those with one phase.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2010 Issue 1, Copyright © 2010 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This version first published online:
July 19. 2006 AbstractBackgroundSide effects of oral contraceptive (OC) pills discourage adherence to and continuation of OC regimens. Strategies to decrease adverse effects led to the introduction of the triphasic OC in the 1980s. Whether triphasic OCs have higher accidental pregnancy rates than monophasic pills is unknown. Nor is it known if triphasic pills give better cycle control and fewer side effects than the monophasic pills. ObjectivesTo compare triphasic OCs with monophasic OCs in terms of efficacy, cycle control, and discontinuation due to side effects. Search strategyWe searched the computerized databases of MEDLINE, EMBASE, POPLINE, LILACS and CENTRAL, as well as clinical trials databases (ClinicalTrials.gov and ICTRP). Additionally, we searched the reference lists of relevant articles and book chapters. We also contacted researchers and pharmaceutical companies to identify other trials not found in our search. Selection criteriaWe included randomized controlled trials (RCTs) comparing any triphasic OC with any monophasic pill used to prevent pregnancy. Interventions had to include at least three treatment cycles. Data collection and analysisWe assessed the studies found in the literature searches for possible inclusion and for their methodological quality. We contacted the authors of all included studies and of possibly randomized trials for supplemental information about the methods and outcomes studied. We entered the data into RevMan 4.2 and calculated odds ratios for the outcome measures of efficacy, breakthrough bleeding, spotting, withdrawal bleeding and discontinuation. Main resultsOf 21 trials included, 18 examined contraceptive effectiveness: the triphasic and monophasic preparations did not differ significantly. Several trials reported favorable bleeding patterns, i.e. less spotting, breakthrough bleeding or amenorrhea, in triphasic versus monophasic OC users. However, meta-analysis was generally not possible due to differences in measuring and reporting the cycle disturbance data as well as differences in progestogen type and hormone dosages. No significant differences were found in the numbers of women who discontinued due to medical reasons, cycle disturbances, intermenstrual bleeding or adverse events. Authors' conclusionsThe available evidence is insufficient to determine whether triphasic OCs differ from monophasic OCs in effectiveness, bleeding patterns or discontinuation rates. Therefore, we recommend monophasic pills as a first choice for women starting OC use. Large, high-quality RCTs that compare triphasic and monophasic OCs with identical progestogens are needed to determine whether triphasic pills differ from monophasic OCs. Future studies should follow the WHO recommendations on recording menstrual bleeding patterns and the CONSORT reporting guidelines. |