Congenital Bilateral Absence of Vas Deferens (CBAVD)
Last Updated: April 7, 2020
Definition - What does Congenital Bilateral Absence of Vas Deferens (CBAVD) mean?
Congenital bilateral absence of the vas deferens (CBAVD) is a condition in which the tubes that carry the sperm out of the testicles, called the vas deferens, do not develop properly and are not formed at birth.
CBAVD greatly impacts a man's fertility because sperm cannot be transported from the testes to the ejaculate, meaning the affected couple will be unable to conceive naturally. This complete lack of sperm in semen is called azoospermia. However, men may have normal levels of sperm in the testes.
FertilitySmarts explains Congenital Bilateral Absence of Vas Deferens (CBAVD)
CBAVD accounts for 1 to 2% of cases of infertility in men and around 6% of cases of obstructive azoospermia.
The vas deferens is a part of the male reproductive tract that functions to transport sperm out of the testicles. Its function is similar to the Fallopian tubes, which function to transport the eggs out of the ovaries.
The absence of vas deferens can be unilateral (one-sided) or bilateral (two-sided.)
The bilateral absence of vas deferens is a more prevalent variety of this disorder in which both tubes are absent. This condition is associated with a genetic disorder called cystic fibrosis (CF).
The unilateral absence of vas deferens is a less common variation of this condition. Men with unilateral absence of vas deferens can conceive naturally as long as the testicles and vas deferens of the other side are functional.
Men with unilateral absence of the vas deferens are more likely to have other medical conditions including the absence of the kidney on the same side.
How is CBVAD diagnosed?
A CBAVD diagnosis is made on physical examination and confirmed after tests like scrotal ultrasound or transrectal ultrasound (TRUS). A semen analysis is also important to determine the sperm count. Men with this condition should undergo genetic testing.
For men with CBAVD, sperm can be retrieved from the body, bypassing the function of the vas deferens. Options include:
Microsurgical epididymal sperm aspiration (MESA)
Extracted sperm can then be used in in vitro fertilization (IVF) with intracytoplasmic sperm insemination (ICSI). Donor sperm is also an option.
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Chillon M, et al.
Mutations in the Cystic Fibrosis Gene in Patients with Congenital Absence of the Vas Deferens.