Gestin (allylestrenol) is a synthetic progestogen, or progestin, used in conception or pregnancy complications in women at least 16 years old. It is also sometimes used in men to help treat benign prostatic hyperplasia, better known as an enlarged prostate.

Many women will be familiar with progestin use in combined birth control contraceptives. Gestin is not used for this purpose, as it differs in both function and dosage. It is not combined with estrogen or any other hormone, and is not used as a progestin-only pill except to treat difficulties conceiving or maintaining a pregnancy. It is not used in post-menopausal women.

How It Works

Progesterone is a critical fertility and pregnancy hormone. Each month it prepares the uterus for the implantation of a fertilized egg, and, once implanted, it inhibits the immune system from rejecting the fetus, promotes nourishment, prevents further ovulation, and promotes growth of glands needed for milk production.

If progesterone levels are too low implantation will not occur or the uterus can become inhospitable to the fetus, resulting in miscarriage or premature labor. Gestin helps resolve these issues, as it:

• Promotes conception in women who have difficultly becoming pregnant
• Reduces risk of miscarriage
• Prevents premature labor
• Alleviates effects in certain other pregnancy complications

Unfortunately the above pregnancy difficulties can have many causes completely unrelated to progesterone levels, in which cases Gestin will do nothing. Only a doctor can determine progesterone levels.

Gestin is also used in some locations---notably Japan---to treat enlarged prostates and alleviate associated symptoms. The medication slows, stops, or reverses prostate growth, thus allowing improved passage of urine.

Gestin for a Healthy Pregnancy

Gestin may be prescribed in several circumstances:

• Progesterone levels are determined to be low
• A woman is unable to conceive after trying for some period of time
• A woman has had two or more consecutive miscarriages
• Low progesterone is detected during pregnancy, causing concern for premature labor

If low progesterone levels have been established, Gestin may be prescribed to prevent other complications as well.

Gestin only come in 5 mg tablets. Tablets should be swallowed whole and not split or crushed unless explicitly advised to do so by a doctor. Tablets can be taken with or without food as desired.

Dosing is largely individualized. It typically ranges from 10 to 40 mg per day for conception; use in pregnancy is more variable and should be determined by a doctor. In both cases treatment typically lasts for one week at a time, though there are exceptions.

Daily doses are usually divided into two or three smaller doses taken throughout the day, though again there are exceptions.

Again it's important to understand that this medication will only help when low levels of progesterone are causing problems. If levels are not low Gestin will not help. If levels are unknown, it probably will not help as there are many other common causes for these complications.

Alleviating Benign Prostatic Hyperplasia

Benign prostatic hyperplasia refers to non-cancerous growth of the prostate, which can lead to difficulty urinating or completely emptying the bladder, which in turn can lead to more complications, such as bladder stones, urinary tract infections, and kidney damage.

Gestin has proven beneficial in both clinical studies and real-world use for alleviating symptoms, preventing further growth, and reversing growth. Results do, of course, vary between individuals, and there are other medical factors that may also influence effectiveness.

For benign prostatic hyperplasia dosage is typically 50 mg per day, and treatment may continue for months at a time. Use of Gestin is not recommended unless the prostate size is causing complications, such as restricting urination. Many men, despite having enlarged prostates, do not experience these issues.