[Occurrence of bleeding in women using combined hormonal contraceptives (ethinylestradiol 35 micrograms/norgestimate 250 micrograms in relation to regularity of administration and cycle start day].
OBJECTIVE
To assess the frequency of irregular intermenstrual bleeding in combined oral contraceptive (ethinylestradiol 35 micrograms/norgestimate 250 micrograms, COC) users and the influence of regularity of pill use on this frequency; to assess the occurrence of withdrawal bleeding during weekends in women using the COC from the first Sunday in the cycle (Sunday start method).


METHODS
Prospective, open, non-comparative, multicenter study in 27 centers.


METHODS
The first day of the pill use, occurrence of intermenstrual and withdrawal bleeding and regularity of use were assessed by means of patient's bleeding diary. Body weight, blood pressure and side effects were monitored before the oral contraceptive use and after the third cycle.


RESULTS
358 (94%) of 382 women completed the study. Frequency of intermenstrual bleeding was generally low (6.7%, 5.0% and 5.0% in the first, second and third cycle) and highly influenced by regularity of pill use (2.6%, 0% a 1% in regular users versus 30.2%, 32.1% a 24.2% in irregular users). 28%, 40% and 47% of Sunday start users achieved bleeding-free weekends after the first, second and third cycle. Body weight and blood pressure did not change during the study.


CONCLUSIONS
Frequency of intermenstrual (breakthrough) bleeding during the first three months of COC use is highly influenced by regularity of use. In regular users of monophasic COC containing ethinylestradiol 35 micrograms/norgestimate 250 micrograms the frequency of intermenstrual bleeding is bellow 2.6%. In Sunday start users the proportion of women with bleeding-free weekends (i.e. weekends without the occurrence of withdrawal bleeding) increases to 47% after the third cycle.
Paseková
V
V
Centrum reprodukcní medicíny, Brno. v.pasekova@quick.cz
Chroust
K
K
D000293:Adolescent; D000328:Adult; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage / Q000009:adverse effects*; D004338:Drug Combinations; D004997:Ethinyl Estradiol; D019304:Ethinyl Estradiol-Norgestrel Combination / Q000008:administration & dosage / Q000009:adverse effects* / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009644:Norgestrel / Q000031:analogs & derivatives; D010349:Patient Compliance; D011446:Prospective Studies; D014592:Uterine Hemorrhage / Q000139:chemically induced*
D003278:Contraceptives, Oral, Hormonal; D004338:Drug Combinations; C109079:norgestimate, ethinyl estradiol drug combination; D009644:Norgestrel; D004997:Ethinyl Estradiol; D019304:Ethinyl Estradiol-Norgestrel Combination