Oral versus intramuscular progesterone for in vitro fertilization: a prospective randomized study

Area of Science:

• Reproductive Endocrinology
• In Vitro Fertilization (IVF)

Background:

• Luteal support is crucial in IVF cycles utilizing Gonadotropin-Releasing Hormone (GnRH) agonists for pituitary down-regulation.
• Both oral micronized progesterone and intramuscular (IM) progesterone in oil are commonly used for luteal phase support.

Purpose of the Study:

• To compare the efficacy of oral micronized progesterone versus IM progesterone in oil for luteal support in IVF patients undergoing GnRH agonist treatment.
• To evaluate the impact of different progesterone formulations on progesterone levels and key IVF outcomes.

Main Methods:

• A randomized prospective clinical trial was conducted at a university-based IVF center.
• Women under 40 undergoing IVF with GnRH agonist pituitary down-regulation were randomized to receive either oral micronized progesterone (200 mg TID) or IM progesterone (50 mg daily).
• Progesterone levels were measured on days 21 and 28, alongside clinical pregnancy and embryo implantation rates.

Main Results:

• On day 21, progesterone levels were comparable between groups (IM: 77.6 ng/mL, Oral: 81.5 ng/mL).
• On day 28, progesterone levels were significantly lower in the oral group (IM: 76.3 ng/mL, Oral: 53.6 ng/mL).
• Clinical pregnancy rates were 57.9% for IM and 45.8% for oral progesterone. The implantation rate per embryo was significantly higher with IM progesterone (40.9%) compared to oral (18.1%).

Conclusions:

• While both oral and IM progesterone formulations yield comparable circulating progesterone levels initially, IM progesterone demonstrated superior outcomes in this study.
• Oral micronized progesterone resulted in a reduced implantation rate per embryo in IVF patients undergoing GnRH agonist treatment.
• These findings suggest that IM progesterone may be a more effective option for luteal support in specific IVF protocols.