Does Testosterone Therapy Cause Male Infertility?

What does the evidence say about testosterone therapy and male fertility during pregnancy?

1. Testosterone therapy suppresses the body's own hormone signaling: rising testosterone tells the brain to reduce the signals (GnRH, then LH and FSH) that trigger sperm production, which is why testosterone therapy on its own can lower or stop sperm counts. 1
2. Because testosterone therapy suppresses sperm production, it isn't recommended for men who want to have a child in the near future; gonadotropin therapy (hCG or FSH) is used instead when near-term fertility is a goal, and induced spermatogenesis in about 75% of men with gonadotropin-related hypogonadism in one meta-analysis. 2
3. How long it takes for sperm production to recover after stopping testosterone therapy depends on the formulation: averaging about 5 to 6 months after long-acting injectable testosterone, roughly 6 to 12 months after medium-acting injectable forms, and closer to 3 months after shorter-acting gel or oral forms. 1
4. In a nationwide study of pregnancies conceived using assisted reproduction, researchers excluded men who had been prescribed testosterone therapy within the 6 months before their partner's estimated conception date, reflecting how strongly testosterone therapy is understood to suppress fertility during that window. 3
5. NICHD's overview of male infertility causes lists hormone imbalances, including conditions related to androgens like testosterone, among the recognized contributors to reduced fertility in men. 4

Is testosterone therapy and male fertility safe in each trimester?

• First trimester. If your partner is already on testosterone therapy when you start trying, ask his prescriber about a baseline semen analysis, since therapy alone can already be suppressing sperm counts.
• Second trimester. If pregnancy hasn't happened after several months of trying and your partner is on testosterone therapy, that therapy is a reasonable thing to raise at a fertility evaluation, since it's a common and often overlooked contributor.
• Third trimester. If a fertility workup points to low sperm counts tied to testosterone therapy, his prescriber may switch to a fertility-preserving option like gonadotropin therapy or clomiphene instead, which can support symptoms and sperm production at the same time.