The goal of the vasectomy reversal procedure is to surgically re-establish the normal flow of sperm. Factors which influence success rates include the type of connection needed (vas-to-vas vs. vas-to-epididymis), surgical technique used, as well as the genetics of the individual man, as some men are prone to form more or less scar tissue in this area as they heal. Sperm counts and quality often take time to improve following a reversal as the system adjusts to its new non-obstructed environment. Typically sperm enter the ejaculate within 3-6 months following reversal surgery, but it can take longer or shorter amounts of time in individual circumstances.
In general, normal sperm counts are defined as 15-20 million sperm/cc with a motility (% of sperm swimming) of greater than or equal to 50%. Morphology (the % of sperm with perfectly normal shapes) is highly lab-dependent and its association with fertility outcomes is less clear. The goal is to get the highest number of best quality sperm possible for optimal rates of pregnancy. Fertility is still possible with sperm counts less that those in the 'normal' range, but you typically like to see a return of at minimum 5 million sperm/cc to have a good chance of pregnancy, either naturally or with the assistance of 'low tech' interventions such as intrauterine inseminations (IUI). Sperm typically return within 3-6 months, and often increase in number and quality over the first year.
Dr. Russell's Success Rates (chance of sperm returning in good numbers):
Vas-to-vas connection on each side: >90%
Vas-to-vas on one side and vas-to-epididymis on the other side
(as each side is checked individually): 80%
Vas-to-epididymis connection each side: 55-60%
Predictions of natural pregnancy rates are always less accurate for a particular couple than patency rates (i.e. sperm returning in good numbers). Patency rates indicate a technically successful procedure and relate only to the procedure performed and a man's natural (genetic) tendencies for scar tissue formation in the vasal area. On the other hand, natural pregnancy rates reflect such diverse factors as: potential female fertility issues which might be present, elements of chance associated with the process of natural conception, and the potential presence of anti-sperm antibodies (which can form at the time of the initial vasectomy). Fortunately, anti-sperm antibodies only rarely cause fertility problems following a successful reversal (a common misperception in the field of fertility). In general, when sperm has returned in good numbers, then a couple can expect to conceive a child naturally around 2/3rds of the time, with a higher percent conceiving a child by adding assistance from the female side with such treatments as Clomid and/or intrauterine inseminations.
