From the Guidelines
A vasectomy does not typically raise FSH (follicle-stimulating hormone) levels in men. After a vasectomy, the testes continue to produce sperm and testosterone normally, and the hormonal regulation system remains intact. The procedure only blocks the vas deferens, preventing sperm from entering the ejaculate, but does not affect hormone production or regulation. The hypothalamic-pituitary-gonadal axis, which controls FSH production, continues to function as before. FSH levels might temporarily fluctuate immediately after the procedure due to surgical stress, but they generally return to baseline quickly. In rare cases where complications like testicular damage occur, there might be some hormonal changes, but this is not typical with properly performed vasectomies. Men who have had vasectomies can expect their hormonal profiles, including FSH levels, to remain essentially unchanged from their pre-vasectomy state.
According to the most recent guidelines, obstructive azoospermia is suspected if the physical examination reveals testes of normal size, fully descended into the scrotum and bilaterally dilated and/or indurated epididymides with or without absence of the vas deferens, and FSH levels are usually less than approximately 7.6 IU/L 1. This suggests that a vasectomy, which is a form of obstructive azoospermia, would not typically raise FSH levels.
Some key points to consider:
- Azoospermia is defined as absence of sperm in the ejaculate, and a vasectomy would result in azoospermia in the ejaculate, but not affect FSH levels 1.
- FSH levels are used to differentiate between obstructive and non-obstructive azoospermia, with obstructive azoospermia typically having lower FSH levels 1.
- Clinicians should recommend karyotype testing for males with primary infertility and azoospermia or sperm concentration <5 million sperm/mL when accompanied by elevated FSH, testicular atrophy, or a diagnosis of impaired sperm production 1.
Overall, the current evidence suggests that a vasectomy does not typically raise FSH levels in men, and men who have had vasectomies can expect their hormonal profiles, including FSH levels, to remain essentially unchanged from their pre-vasectomy state 1.
From the Research
Effects of Vasectomy on FSH Levels
- The relationship between vasectomy and FSH levels has been investigated in several studies 2, 3, 4, 5, 6.
- A study published in 1976 found that mean plasma FSH levels were unchanged 6 months after vasectomy, but a slight elevation occurred by 2 years after the procedure 3.
- Another study published in 2011 found that plasma FSH levels decreased on day 3 after vasectomy in adult male rats, but returned to normal levels thereafter 4.
- A study published in 1988 found that the amplitude of the seasonal variation in FSH was decreased after vasectomy, but the annual mean was unchanged compared to pre-vasectomy levels 5.
- A prospective study published in 1990 found a trend to rise in LH 10 days after vasectomy, but no significant changes in FSH levels were reported 6.
- Overall, the evidence suggests that vasectomy may not have a significant impact on FSH levels in the long term, but some studies have reported slight changes in FSH levels after the procedure 3, 4, 5, 6.