Menstrual cycle shortest and longest cycle lengths is considered very irregular. The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39. Subsequently, the variability increases slightly for women aged 40 to 44. The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14.13 days, standard deviation 1.41 days) whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).
Progesterone (medication) statement on progesterone in premenstrual syndrome. Progesterone can be used to treat catamenial epilepsy by supplementation during certain periods of the menstrual cycle. Progesterone is available in a variety of different forms, including oral capsules, sublingual tablets, vaginal capsules, tablets, gels, suppositories, and rings; rectal suppositories; oil solutions for intramuscular injection; and aqueous solutions for subcutaneous injection. A 1% topical progesterone gel is approved for local application to the breasts to treat breast pain, but is not indicated for systemic therapy. Progesterone was previously available as an intrauterine device for use in hormonal contraception, but this formulation was discontinued. Progesterone