A randomized double blind
clinical trial was carried out at the Division of
Family Planning, Siriraj
Hospital in order to study the
efficiency of
low dose oral contraceptive pills, containing 0.03 mg
ethinyl estradiol and 0.15 mg levonorgestel, for postponement of
menstruation. Sixty hralthy
women with previous regular
menstruation were randomly assigned to one of two study groups. Thirty
women in the
control group received 10
capsules of a placebo and the other 30
women in the study group received 10
capsules that contained the
oral contraceptives. The
women in both groups began taking the in doses of one
capsule per day for three days before the expected date of
menstruation. The characteristics of both groups were comparable. The number of
women who expected postponement of their
menstruation were recorded together with the side-effects. The results showed that
oral contraceptive pills taken three days before the expected date of
menstruation could postpone
menstruation significantly (27/30 vs 2/30, p< 0.05). The major side-effects were
headache (10 percent) and
nausea (13.3 percent).