Subcutaneous Progesterone Versus Vaginal Progesterone Tablets for Luteal Phase Support in In Vitro Fertilization (IVF)

Inclusion Criteria: * Patient has given written informed consent; * BMI \< 30 kg/m2; * Age 18 - 42 (upon starting COH); * \<3 prior ART cycles (IVF, ICSI and related procedures); * Baseline (day 2-3 of cycling) FSH \<15 IU/L and E2 \<80 pg/mL; * Normal uterine cavity as per recent hysterosalpingogram, sonohysterogram or hysteroscopic exam (i.e. no polyps or protruding submucosal fibroids); * Patients must have at least three retrieved oocytes. Exclusion Criteria: * Intramural uterine fibroids that distort the uterine cavity or polyps \>1 cm; * Stage III or IV endometriosis (no endometriomas); * Hydrosalpinges; * History of past poor response to COH resulting in canceling ART; * Use of thawed/donated oocytes; * Use of thawed/donated embryos; * Gestational carrier; * Patients affected by pathologies associated with any contraindication of being pregnant; * Hypersensitivity to study medication; * Uncontrolled adrenal or thyroid dysfunction; * History of conditions (i.e. toxic shock syndrome) that would contraindicate use of a vaginal progesterone product; * History of arterial disease; * Patients with hepatic impairment (liver function tests \> 2x upper limits of normal); * Patients with dermatologic disease; * Patients with renal impairment (estimated creatinine clearance \<60 mL/min/1.73 m2); * Neoplasias (current) or history of neoplasia that may be responsive to progesterone; * High grade cervical dysplasia; * History of recurrent pregnancy loss defined as 3 or more spontaneous miscarriages, wherein pregnancy developed to a minimum of a gestational sac on TVUS; * Participation in a concurrent clinical trial or in another trial within the past 2 months; * Use of concomitant medications that might interfere with the study evaluation; * Pre-implantation genetic diagnosis/screening