Assessing changes in vaginal bleeding patterns in contracepting women.

ABSTRACT

PIP: Researchers recruited 1216 females to study changes in amenorrhea patterns with successive injections of the long acting injectable contraceptive depot-medroxyprogesterone acetate (DMPA). The women received an injection of either 100 mg or 150 mg DMPA on the day of randomization and 3 additional injections at 90 day intervals. 1151 (94.7%) women completed a menstrual diary that could be used, but only diaries of at least 60 days were considered in each reference period (90 days). Of the 99 who received only 1 100mg injection, 23 had amenorrhea. Of the 361 receiving 4 injections, 142 experienced no amenorrhea in any of the injection intervals and 30 had amenorrhea in all 4 intervals. Overall 281 women out of 576 who received 1-4 injections of 100 mg DMPA did not experience amenorrhea at all. For those in the 150 mg sample receiving 1-4 injections, 237 out of 575 women did not have amenorrhea. Analysis of change over time suggested an increase incidence of amenorrhea following the 2nd injection. In terms of the probability of a woman accepting a injection, women who experienced amenorrhea with the 1st injection were less likely to accept a 2nd, especially in the 150 mg DMPA group. Additionally, the trend in amenorrhea pattern demonstrated that a 3rd injection was adversely affected by amenorrhea in the 2nd injection interval in the 150 mg group but not the 100 mg group. Nevertheless, the decision to have a 4th injection appeared adversely affected by amenorrhea in the 3rd injection interval in both groups. The conditional probabilities used in this research can also be applied to examine continuation or survival rates in a follow-up study based on any prognostic factors.