Ejaculation is the ejection of semen out of the urethra (passageway inside the penis) when a man has an orgasm. Under normal circumstances, ejaculation propels semen forward through a man's urethra and out the tip of his penis. This is because a tiny sphincter (circular muscle) at the entrance to the bladder shuts the opening to the bladder and prevents semen from entering. Retrograde ejaculation is when the semen travels backwards into the bladder.
In retrograde ejaculation, the muscle that shuts the bladder does not function normally. This allows all or part of the semen to travel backward (retrograde) into the bladder at the time of ejaculation. When this happens, less semen comes out the tip of the penis.
Retrograde ejaculation has several possible causes, including:
Damage from surgery to the muscles of the bladder, or to the nerves that control these muscles — This damage can occur as a complication of the following surgical procedures:
Prostate surgery — Men who have had a transurethral prostatectomy (removal of prostate tissue through the urethra) have a 10-15 % chance of retrograde ejaculation. A prostatectomy (surgery to remove the entire prostate gland, either for cancer or benign enlargement) results in a higher risk of retrograde ejaculation after the procedure.
Surgery on certain parts of the bladder
Extensive pelvic surgery, especially to treat cancer of the prostate, testicles, colon or rectum
Staging surgery for cancer in the pelvis or lower abdomen (this surgery removes lymph nodes in the pelvis and lower abdomen to help determine how far cancer has spread)
Certain types of surgery on the discs and vertebrae of the lower spine
Nerve damage caused by medical illness — This is especially common in men with multiple sclerosis or with long-term, poorly controlled diabetes.
Side effects of medication — Medications that may cause retrograde ejaculation include drugs to treat:
Prostate enlargement — tamsulosin (Flomax) or terazosin (Cardura)
Depression -- especially selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac), sertraline (Zoloft) and several others
Psychosis -- such as chlorpromazine (Thorazine), thioridazine (Mellaril) and risperidone (Risperdal)
Retrograde ejaculation does not interfere with a man's ability to have an erection or to achieve orgasm, but it can cause infertility because the sperm cannot reach the woman's uterus. Retrograde ejaculation is responsible for about 1% of all cases of male infertility in the United States.