What is the likelihood of pregnancy with cyclic progesterone (a hormone) therapy to induce ovulation?

From the Research

Cyclic progesterone therapy alone is not effective for inducing ovulation and has a very low chance of resulting in pregnancy. For women seeking to induce ovulation, medications like clomiphene citrate (50-100mg daily for 5 days) or letrozole (2.5-7.5mg daily for 5 days) are the first-line treatments, with success rates of 60-80% for ovulation induction and pregnancy rates of approximately 30-40% per cycle when used appropriately 1. Some key points to consider:

• Progesterone is actually used after ovulation has occurred, either to support the luteal phase or to induce withdrawal bleeding when given cyclically (typically 10mg daily for 10-14 days each month) 2.
• The confusion may arise because progesterone withdrawal can sometimes trigger the hypothalamic-pituitary axis to initiate a new cycle, but this doesn't directly induce ovulation.
• For effective ovulation induction, you need medications that either block estrogen receptors (clomiphene) or reduce estrogen production (letrozole), which increases follicle-stimulating hormone (FSH) release from the pituitary gland, stimulating follicular development and ovulation 3, 1.
• If you're trying to conceive, consult with a reproductive endocrinologist who can recommend appropriate ovulation induction medications based on your specific situation. Some studies have shown that luteal phase progesterone supplementation can improve endometrial receptivity and clinical pregnancy rates in women undergoing treatment with clomiphene citrate in combination with intrauterine insemination (CC-IUI) 4. However, the most recent and highest quality study on this topic is from 2017, which found that clomiphene citrate or letrozole with or without gonadotropins compared to use of gonadotropins along with gonadotropin-releasing hormone (GnRH) agonists or antagonists resulted in a similar live birth rate and clinical pregnancy rate, but with a reduction in the incidence of OHSS 1. Therefore, the most effective treatment for inducing ovulation and achieving pregnancy is still clomiphene citrate or letrozole, with or without gonadotropins, rather than cyclic progesterone therapy alone.