Spina bifida (SB) is a birth defect that occurs when the neural tube, which forms the brain and spinal cord, does not close completely during early pregnancy. While known for its effects on mobility and bladder function, SB also introduces specific challenges concerning fertility in men. The primary hurdle to fatherhood is typically the neurological control required for sperm delivery, rather than the ability to produce sperm. With modern medical interventions, however, the reproductive potential for men with spina bifida has significantly improved, allowing many to successfully conceive.
Neurological Impact on Ejaculation
The most common cause of infertility in men with spina bifida is a dysfunction in the process of ejaculation, which is controlled by the autonomic nervous system. The nerve damage resulting from the spinal cord defect often disrupts the complex signals needed for the two phases of ejaculation: emission and expulsion. This neurological disruption is directly related to the level of the spinal cord lesion; men with higher lesions typically experience more severe dysfunction.
Many men with spina bifida experience anejaculation, which is the complete failure to release semen, or retrograde ejaculation, where semen travels backward into the bladder instead of forward out of the urethra. Studies suggest that up to 75% of men with spina bifida may experience some form of ejaculatory issue. Even when ejaculation occurs, it is often described as weak or a slow, dripping emission, which is insufficient for natural conception. This mechanical failure prevents sperm from reaching the female reproductive tract.
The ability to achieve an erection can also be affected, though this is a separate issue from ejaculation, and many men can achieve an erection with or without the aid of medication. Infertility remains centered on the inability to deliver the sperm-containing fluid to the partner, requiring specialized medical intervention to retrieve the sperm for use in assisted reproduction.
Sperm Health and Viability
A common concern is whether the sperm itself is healthy and viable for fertilization. Spina bifida does not inherently prevent the testes from producing sperm, a process known as spermatogenesis. Hormonal levels that regulate sperm production are usually within the normal range for men with this condition.
Men with spina bifida can experience secondary issues that negatively impact sperm quality, leading to lower counts, poor motility, or abnormal shape. Cryptorchidism (undescended testes) occurs more frequently and can impair sperm development due to higher body temperatures. Chronic urinary tract infections or prolonged sitting, which affects scrotal temperature regulation, may also contribute to reduced sperm viability.
Sperm quality is often diminished compared to the general population, even in samples provided naturally or through assisted means. Many men with spina bifida are found to have either no sperm in their ejaculate (azoospermia) or very low sperm concentrations. Therefore, sperm quality must be assessed when planning for fatherhood.
Assisted Reproductive Options
When natural conception is prevented by ejaculatory dysfunction, several effective medical procedures are available. The most common and successful method for obtaining a sperm sample is electroejaculation (EEJ). This procedure uses a specialized rectal probe to deliver a mild electrical current, stimulating the nerves that control ejaculation and causing semen to be released.
Electroejaculation is typically performed under anesthesia and is effective in retrieving sperm, even in cases of anejaculation. If the semen sample collected contains sufficient numbers of motile sperm, it can sometimes be used for intrauterine insemination (IUI). However, due to the frequently compromised quality of retrieved sperm, or if EEJ is unsuccessful, more advanced techniques are often necessary.
If no sperm is retrieved or the quality is too poor, surgical methods like Testicular Sperm Extraction (TESE) or Percutaneous Epididymal Sperm Aspiration (PESA) can be utilized to retrieve sperm directly from the reproductive tract. The retrieved sperm is then typically used in Intracytoplasmic Sperm Injection (ICSI), a form of In Vitro Fertilization (IVF). ICSI involves injecting a single, healthy sperm directly into an egg, which overcomes issues with low sperm count or poor motility and increases the chances of successful fertilization.
Understanding Inherited Risk
Spina bifida is considered a multifactorial condition, meaning it results from a complex interaction between genetic predisposition and environmental factors. While the condition is not inherited in a simple pattern, having a parent with spina bifida does increase the risk for the child. The risk of recurrence when one parent has spina bifida is generally cited as being around 4%, which is higher than the risk in the general population.
Genetic counseling is recommended for couples planning to conceive, allowing for a thorough assessment of specific family history and risk factors. The most significant preventative measure is the use of high-dose folic acid supplementation by the female partner before and during the earliest stages of pregnancy. Women who are at high risk, such as those with a partner who has spina bifida, are advised to take a higher dose, typically 4 milligrams per day, starting at least one month before conception.
Folic acid supplementation can reduce the risk of a neural tube defect by up to 70%. By combining advanced reproductive techniques with proactive preconception care, couples can navigate the challenges of spina bifida while mitigating the risk of passing the condition to their child.