Key Exam Points — Infertility

Definition of infertility: failure to achieve clinical pregnancy after ≥12 months of regular unprotected intercourse; evaluate after 6 months if female partner is over 35.
Male factor is solely responsible in ~20% and contributes to ~30–40% of infertile couples.
Most common identified causes of male infertility: idiopathic (33%), varicocele (27%), obstruction (15%), endocrinopathy (10% — hypogonadism most common).
Klinefelter syndrome is the most common known genetic cause of male infertility; Y chromosome microdeletion is second most common.
AZFa or AZFb complete microdeletions generally preclude TESE; AZFc microdeletions: sperm may or may not be found at TESE.
CFTR mutations are present in up to 80% of CBAVD, 20% of CUAVD, and 21% of idiopathic epididymal obstruction; partner CFTR testing is required before ART.
Up to 26–75% of men with unilateral vasal agenesis and ~10% with CBAVD have ipsilateral renal agenesis — obtain renal US if not a CFTR carrier.
Testosterone monotherapy must not be prescribed to men interested in current or future fertility because it suppresses LH/FSH and intratesticular testosterone.
Exogenous testosterone causes acquired hypogonadotropic hypogonadism with low/undetectable FSH/LH, atrophic testes, and severe oligozoospermia or azoospermia; recovery typically begins 4–5 months after cessation and may take up to 2 years.
WHO 5th percentile cut-offs: volume <1.5 mL, total number <39 million/ejaculate, concentration <15 million/mL, total motility <40%, progressive motility <32%, normal forms <4%, vitality <58%.
Causes of low-volume semen include obstruction/hypoplasia of prostate and seminal vesicles, alpha blockers, retrograde ejaculation, hypervolemia, CBAVD, severe androgen deficiency.
Serum FSH + morning total testosterone are indicated in azoospermia, oligozoospermia (<10 million/mL), impaired libido, ED, atrophic testes, or hormonal abnormality on exam.
FSH >7.6 IU/L with testis long axis <4.6 cm suggests spermatogenic dysfunction (~89% likelihood); FSH <7.6 IU/L with testis >4.6 cm suggests obstruction (~96% likelihood).
Karyotype + Y chromosome microdeletion are indicated in primary infertility with azoospermia or severe oligozoospermia (<5 million/mL) with elevated FSH, testicular atrophy, or presumed spermatogenic failure.
TRUS indications: low semen volume with azoospermia and palpable vasa, low semen volume with significant asthenospermia, or symptoms such as painful ejaculation.
Findings of ejaculatory duct obstruction on TRUS: seminal vesicle AP diameter >1.5 cm, ejaculatory duct caliber >2.3 mm, dilated vasal ampulla >6 mm, midline or paramedian prostatic cyst.
Varicocelectomy is indicated for males with palpable varicocele, infertility, and abnormal semen parameters (except azoospermic males); non-palpable varicoceles detected only by imaging should not be repaired.
Micro-TESE is preferred for non-obstructive azoospermia and yields successful extraction ~1.5× more often than non-microsurgical TESE.
Obstructive azoospermia: sperm may be extracted from either testis or epididymis with similar fertilization, pregnancy, and live birth rates.
IUI requires at least 5–10 million total motile sperm after processing; ICSI minimizes the impact of abnormal motility and morphology and only requires viable sperm.
Recurrent pregnancy loss workup in males includes karyotype, sperm DNA fragmentation, and sperm aneuploidy testing.
Inform patients undergoing chemotherapy or radiation to avoid pregnancy for at least 12 months after treatment completion; encourage sperm banking before gonadotoxic therapy.
Vasectomy is the 4th most commonly used contraceptive method and ~1/4 the cost of tubal ligation.
Post-vasectomy risks include hematoma/infection (1–2%), chronic scrotal pain (1–2%), failure, symptomatic nodule (<5%), and change in sexual function; no evidence of increased risk of prostate cancer, CHD, stroke, hypertension, dementia, or testicular cancer.
Recommended methods of vas isolation: no-scalpel technique or other minimally invasive vasectomy technique; conventional vasectomy should not be performed.
Recommended methods of vas occlusion: mucosal cautery ± fascial interposition; open-ended vasectomy with mucosal cautery on abdominal end + fascial interposition; non-divisional extended electrocautery (Marie Stopes technique).
Post-vasectomy semen analysis timing: 2–4 months (2012 AUA) or 3 months (2022 CUA); success = single sample showing azoospermia or rare non-motile sperm (≤100,000 non-motile sperm/mL).
Risk of pregnancy after vasectomy with confirmed azoospermia/RNMS is approximately 1/2000.