Luteal phase support in "in vitro fertilization" (IVF) cycles has been shown to improve pregnancy rates and became a standard of treatment, and progesterone is the first choice considering its safety profile and effectiveness. There are many studies demonstrating that vaginal progesterone is equally efficacious and better tolerated compared to intramuscular progesterone for luteal phase support in IVF cycles. Conversely, although different studies showed that subcutaneous progesterone is equally efficacious compared to vaginal progesterone, patient use satisfaction and compliance were less studied with few evidences are available, that may guide the choice of vaginal progesterone instead of subcutaneous progesterone and other way around. Considering the paucity of published data about the patient's preference and use satisfaction about subcutaneous progesterone, the investigators will conduct a prospective randomized study aimed to compared adverse effects rates, impact on quality of life, use satisfaction and administration preference in women undergoing luteal phase support with vaginal progesterone versus subcutaneous progesterone during IVF cycles, that may guide the choice for luteal phase support in IVF cycles.

Inclusion Criteria:

• Infertile women candidate to undergo fresh IVF cycles

Exclusion Criteria:

• day-3 follicle-stimulating hormone (FSH) levels over 15 IU/L
• clinically relevant systemic disease (e.g., uncontrolled thyroid and adrenal dysfunction, an organic intracranial lesion such as a pituitary tumor, insulin-dependent diabetes mellitus, cancers)
• hypersensitivity to any of the study drugs
• contraindications to use the study drugs
• surgical or medical condition that would interfere with absorption, distribution, metabolism, or excretion of the study drugs