The purpose of this study is to compare the effects (good and bad) of subantimicrobial dose doxycycline on the irregular bleeding women experience when taking continuous oral contraceptive pills. This research is being done because currently, there is no effective treatment for this condition. Findings from this study could help to decrease the side effects of birth control pills and decrease unplanned pregnancies.

Continuous oral contraceptive administration entails women taking hormonally active pills for 28 days without a seven day placebo week to avoid hormonal withdrawal bleeding. Unfortunately, with continuous administration, timed, regular bleeding can be replace by irregular, unscheduled bleeding, which often leads to dissatisfaction, discontinuation and the possibility of unplanned pregnancy.

Matrix Metalloproteinases, a group of zinc-dependant proteases, are hypothesized to play a role in endometrial degradation. The purpose of this study is to describe the expression of Matrix Metalloproteinases in endometrial biopsy specimens collected 1) prior to initiating oral contraceptives 2) while taking cyclic oral contraceptive 3) while taking continuous oral contraceptives and 4) while taking continuous oral contraceptives along with sub-antimicrobial doxycycline.

Inclusion Criteria:

• Women between the ages 18 and 45 who are ovulatory as demonstrated by a pre-treatment Progesterone (P) greater than or equal to 3.0 ng/mL prior to oral contraceptive use

Exclusion Criteria:

• Women with any absolute contraindications to ethinyl estradiol and levonorgestrel;
• Women who are pregnant or breastfeeding
• Use of oral contraceptives, patch, ring, intrauterine or implantable hormonal contraception within 4-weeks;
• Medroxyprogesterone acetate use within six months;
• Current use of drugs that interfere with sex steroid metabolism.