Omitting the first oral contraceptive pills of the cycle does not automatically lead to ovulation.
OBJECTIVE
Our purpose was to test the hypothesis that omitting the first three pills of the contraceptive cycle leads to ovulation.


METHODS
Ninety-nine women, randomly assigned to 1 of 3 treatments of combined oral contraceptives, completed the study. Treatments contained ethinyl estradiol and either monophasic gestodene, triphasic gestodene, or monophasic desogestrel. Pituitary-ovarian activity was monitored by ultrasonography of the ovaries and assay of serum concentrations of estradiol, progesterone, and follicle-stimulating hormone over 1 normal cycle (study period 1) and 1 cycle after an extended pill-free interval of 10 days (study period 2).


RESULTS
None of the women experienced normal ovulation as evaluated by ultrasonography and serum progesterone concentrations. However, follicle-stimulating hormone reached a maximal serum concentration in most women during the first 7 pill-free days, indicating complete pituitary recovery, and increases in serum estradiol concentrations were seen in each woman although with marked interindividual variation. During study period 2 we found follicles of >18 mm in 24%, 24%, and 40% of the monophasic gestodene, triphasic gestodene, and monophasic desogestrel groups, respectively.


CONCLUSIONS
Follicular growth up to preovulatory size is common in women missing the first one to three pills of their contraceptive cycle. Although this creates the prerequisite for ovulation, normal ovulation did not occur when pill omissions were limited to only 3 days.
Elomaa
K
K
Väestöliitto, The Family Federation of Finland, Helsinki.
Rolland
R
R
Brosens
I
I
Moorrees
M
M
Deprest
J
J
Tuominen
J
J
Lähteenmäki
P
P
D000293:Adolescent; D000328:Adult; D003277:Contraceptives, Oral, Combined / Q000627:therapeutic use*; D017135:Desogestrel / Q000627:therapeutic use; D004334:Drug Administration Schedule; D004958:Estradiol / Q000494:pharmacology; D004997:Ethinyl Estradiol / Q000627:therapeutic use; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006801:Humans; D008597:Menstrual Cycle / Q000187:drug effects*; D009652:Norpregnenes / Q000627:therapeutic use; D006080:Ovarian Follicle / Q000187:drug effects / Q000254:growth & development; D010060:Ovulation / Q000187:drug effects*; D011374:Progesterone / Q000494:pharmacology
D003277:Contraceptives, Oral, Combined; D009652:Norpregnenes; C033273:Gestodene; D004997:Ethinyl Estradiol; D011374:Progesterone; D004958:Estradiol; D017135:Desogestrel; D005640:Follicle Stimulating Hormone