Congenital absence of the vas deferens (CAVD) is a condition wherein the vas deferens, the duct that delivers sperm from the testicles to the urethra, does not develop properly prior to birth. There are two types of CAVD conditions: unilateral (CUAVD), or one side, or bilateral (CBAVD), or both sides. Those with CAVD are typically able to create sperm, but due to the absence of the vas deferens, are unable to transport it into the semen, causing azoospermia.

What is CAVD?

Congenital absence of the vas deferens (CAVD) is a medical condition where the vasa deferentia reproductive organs fail to develop properly prior to birth. The vas deferens is responsible for delivering sperm from the testicles to the urethra, and can lead to infertility when improperly developed.

There are two types of CAVD conditions: unilateral (CUAVD), meaning just one testicle is affected, or bilateral (CBAVD), in which both testicles are affected. Those with CUAVD or CBAVD are capable of creating sperm, but are unable to transport it into the semen. This causes azoospermia. Consequently, patients with this condition typically turn to assisted reproductive technologies to conceive. 

CAVD and male fertility

CAVD leads to infertility because without a vas deferens, the body cannot transport sperm from the testicles (where they are produced) to the urethra (where they are ejaculated in the semen). This condition greatly affects a male’s fertility, and often leads to azoospermia. While patients with this condition can produce sperm and have no reduced testicular function, the absence of the vas deferens makes it incredibly difficult to conceive because the sperm cannot be delivered through the urethra. Males suffering from CAVD, whether it is unilateral or bilateral, regularly turn to ART technologies to conceive children. 

Causes of CAVD

CAVD is a congenital disorder. This means this condition is present from birth. Mutations in the CFTR gene (cystic fibrosis transmembrane conductance regulator) can cause CAVD, and in many cases, the presence of CBVAD is linked to cystic fibrosis. In fact, more than half of patients suffering from this condition have mutations in the CFTR gene.

Treatment of CAVD

Treatment of CAVD will ultimately depend on whether or not the vas deferens is completely absent. In the case that the vas deferens is completely absent, surgery is not a viable option. As a result, patients with CAVD turn to ART procedures such as sperm extraction, in which sperm is retrieved surgically directly from the testicles — known as TESE, testicular sperm extraction, or TESA, testicular sperm aspiration. Paired with intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF), this procedure can successfully create a pregnancy. Alternatively, some couples may choose to use a sperm donor.