Twenty or thirty microgram ethinyloestradiol in an oral contraceptive: does it make a difference in the mind and the daily practise of gynaecologists and general practitioners?

OBJECTIVES: Currently, evidence-based guidelines concerning the use of oral contraceptives (OCs) containing either 20 or 30 microg ethinyloestradiol (EE) and the same progestogen, are lacking. We wanted to identify whether Swiss gynaecologists and general practitioners (GPs) have specific criteria on which they base their prescribing habit.

METHODS: Two questionnaires were submitted to 158 physicians. The first one contained a list of possible criteria relevant for decision making and a description of specific clinical situations. The second one concerned actual patients who received either a 20 microg (Yasminelle) or a 30 microg (Yasmin) OC containing the same progestogen drospirenone.

RESULTS: The most relevant criteria for decision making (in hierarchical order) were family history of venous thromboembolic disease (VTE), headache, smoking, age beyond 35, stability of the menstrual cycle, breast tenderness, body mass index, irregular bleeding and acne. The 20 microg dosage was preferred for women older than 35, those smoking more than 15 cigarettes per day, those with a family history of VTE, and those complaining of breast tenderness or headache. The 30 microg dosage was preferred for patients with a history of irregular bleeding, a family history of osteoporosis, expected poor compliance and acne.

CONCLUSION: Swiss gynaecologists and GPs do not preferentially prescribe the lowest possible dosage of EE. They use indirect markers they consider relevant for differential prescribing. For some markers, there is inconsistency, indicating that preferences for 20 microg and 30 microg preparations may be influenced by other factors.