What are the defects of seminal vesicles and how it affects fertility?

There are many factors that cause infertility in men. A defect in seminal vesicles is one of them. Dysfunction or malformations in the seminal vesicle can cause infertility in men.

What are Seminal Vesicles?

Seminal vesicles are a pair of lobulated glands located within the male pelvis. The fluid secreted from the seminal vesicles form about 70 percent of the volume of the semen, which is approximately 1.5 ml to 2 ml of the 3 ml ejaculate volume. These secretions play a vital role in proper functioning and survival of sperms.
The component of these secretions consists of:

Fructose
Prostaglandins
Alkaline fluid
Potassium
Phosphorous
Coagulating proteins

Fructose provides energy to the sperm. Prostaglandins are hormones that lower the female immune response to semen. Proteins form a gel-like layer on the sperm that helps in semen coagulation. Phosphorus and potassium help in sperm motility. Alkaline fluid neutralises the acidic nature of male urethra and female vagina.
Let's take a look at the impact of seminal vesicles on infertility:

Defects of Seminal Vesicles and Infertility

The defect of Seminal Vesicles can lead to infertility and following are the conditions that lead to the defect:

Dilated Seminal Vesicles

This condition leads to partial or complete ejaculatory obstruction, in which one or both of the ejaculatory ducts are blocked. This affects the semen volume. A dilated seminal vesicle can be diagnosed by a transurethral ultrasound or by a fructose test. Men with this condition have low volume acidic ejaculate, oligoasthenosprmia, obstructive Azoospermia and poor progressive motility, which affects their fertility too.

Seminal Vesicle Cysts

Cysts in seminal vesicles may or may not produce any visible symptoms. Some of these conditions are either congenital or acquired. Scarring from infection or prior prostate surgery can lead to acquired seminal vesicles.

Seminal Vesicle Stones and Calcification

Stones in seminal vesicles are formed due to inflammation or structural abnormalities in them. Calcification can be caused due to diabetes mellitus, infection, post-obstructive disease and hyperthyroidism. Though this condition is rare, it can lead to Ejaculatory duct obstruction and other complications that may result in infertility.

Seminal Vesicle Agenesis

Seminal vesicle agenesis can be either unilateral or bilateral. This condition may lead to obstructive Azoospermia and other abnormalities in semen

Mega Seminal Vesicles

Mega seminal vesicle is a rare condition that is caused due to a disorder of seminal vesicle contraction and it can lead to functional obstruction of the ejaculatory duct obstruction.