FSH Decrease After Grade 2 Bilateral Varicocele Repair
A decrease in FSH levels after grade 2 bilateral varicocele repair is a favorable prognostic sign indicating improved testicular function and recovery of spermatogenesis. 1, 2
What the FSH Decrease Indicates
The reduction in FSH following varicocele repair reflects:
Restoration of testicular Leydig cell function - The decrease occurs because improved testicular function reduces the negative feedback signal that drives FSH elevation, indicating recovery of the hypothalamic-pituitary-gonadal axis 1, 2
Improved spermatogenesis - Lower FSH levels correlate with better testicular function and spermatogenic capacity, as FSH elevation typically indicates testicular dysfunction or spermatogenic failure 3, 4
Relief of testicular stress - Varicocele repair addresses the underlying pathophysiology (elevated scrotal temperature, testicular hypoxia, toxic metabolite reflux) that was driving FSH elevation 5
Expected Timeline and Magnitude
FSH decreases by approximately 0.48 ng/dL on average after varicocelectomy, with a range of 0.1 to 4.8 ng/dL reduction 2
Changes become apparent at 3 months post-surgery, paralleling the timeline for semen parameter improvements (approximately two spermatogenic cycles or 3-6 months) 6, 1
The decrease is statistically significant across multiple studies, with meta-analysis confirming this finding (95% CI 0.19-0.77, P = 0.001) 2
Clinical Significance by Baseline FSH
For patients with elevated preoperative FSH:
- FSH reduction is more pronounced and clinically meaningful 4
- Patients with grade 3 varicocele, testicular hypotrophy, and grade 4 spermatic vein reflux show the most significant FSH reduction after surgery 4
- Preoperative FSH <11.7 mIU/mL predicts better fertility outcomes after repair 7
For patients with normal baseline FSH:
- The decrease may be modest but still reflects improved testicular function 1
- Even eugonadal patients show measurable FSH reduction, though less dramatic than in hypogonadal patients 1
Associated Hormonal Changes
Along with FSH decrease, expect:
Significant LH reduction - LH decreases by approximately 0.58 ng/dL (range 0.2-2.1 ng/dL), reflecting improved testosterone production 2, 8
Testosterone elevation - Particularly significant in hypogonadal patients (from 215 ng/dL to 327 ng/dL), with the testosterone increase driving the FSH/LH decrease through negative feedback 1, 8
SHBG reduction - Mean decrease of 32.72 nmol/L post-surgery 3
Correlation with Fertility Outcomes
The FSH decrease predicts:
Improved semen parameters - Sperm motility shows very significant improvement (p<0.0005 in infertility patients), with semen volume and morphology also improving 8
Better pregnancy rates - Approximately 37% pregnancy rate achieved after varicocele repair in studies with FSH normalization 8
Spontaneous pregnancy typically occurs 6-12 months post-surgery, after hormonal and semen parameters have stabilized 5
Important Caveats
Grade 2 bilateral varicocele is less common - Most varicoceles are unilateral left-sided; bilateral presentation warrants careful evaluation to exclude secondary causes 3
FSH decrease alone does not guarantee fertility - While favorable, it must be interpreted alongside semen parameters, testicular volume (combined volume ≥30 mL predicts better outcomes), and partner factors 7
Monitor for adequate response - If FSH remains elevated (>7.6 IU/L) at 3-6 months post-surgery, consider evaluation for persistent testicular dysfunction or non-obstructive azoospermia 3
Quality of evidence is moderate - Most studies are observational with small sample sizes; large-scale randomized controlled trials are needed for definitive conclusions 2