Insights in Endocervical Mucus Secretion

Inclusion Criteria:

* Normal menstrual cycles of 25-35 days in length for at least the previous 3 cycles
* BMI \>18 and \<35
* Serum p4 \>= 3 ng/ml on single sample collected between days 18-25 of self-reported menstrual cycle
* Flexible schedule allowing blood draws on less than 48 hour notice
* In good general health
* Commit to using non-hormonal contraceptive methods without spermicide during study period except those prescribed in the experimental protocol
* No objections to taking study drugs
* No objections to refraining from intercourse the night before any sampling and willing to use condoms during vaginal intercourse

Exclusion Criteria:

* Oral contraceptive use or other hormone supplement within the preceding 2 months
* Current cervical infection
* Evidence of abnormal cervical cytology
* Use of any IUD for contraception
* Long-acting hormonal contraceptive use in the past 12 months (e.g., Depo-Provera)
* Contraindications to study drugs
* Current or past pregnancy within the previous 6 months or currently trying to conceive
* Desiring to conceive in the next 8 months
* Breastfeeding in the past 2 months
* Diagnosed diabetes or metabolic syndrome
* Diagnosed Polycystic Ovary Syndrome
* History of, or self-reported, substance abuse
* Smoker
* Previous infertility treatment excluding male factor issues
* Use of an investigational drug within the past 2 months
* History of excisional or ablative treatment procedure on cervix (i.e., LEEP, Cryotherapy, Cold Knife Cone)
* Current treatment for a vaginal infection such as bacterial vaginosis
* History of venous thromboembolism (VTE) or inherited thrombophilias