A 34-year-old male undergoes vasectomy. Which of the following is the most frequent immediate complication of this procedure?

Vasectomy is performed by isolating the vas deferens, cutting it, and closing the ends by either fulguration or ligation. Complications that may arise include hematoma in up to 5% of subjects, sperm granulomas (inflammatory responses to sperm leakage), spontaneous reanastomosis, and, rarely, infections. Sexual function following healing is rarely affected.