Beber Líquidos Pode Afetar o Resultado do Teste de Gravidez? A Verdade Sobre a Diluição

Drinking liquids (water, tea, coffee) does not cause false negatives but can reduce test sensitivity if urine becomes very dilute.

Mecanismo

• Pregnancy tests detect hCG concentration (mIU/mL), not total amount.
• Excessive hydration → low urine specific gravity → hCG concentration may fall below test threshold (25 mIU/mL for standard tests).
• This is a false negative due to dilution, not chemical interference.

Evidence

• Tea, coffee, water—no direct effect on hCG molecule or antibody binding.
• Caffeine is a mild diuretic; increases volume, decreases concentration.
• Alcohol similarly dilutes.

Best Practice

• Use first-morning urine (naturally concentrated overnight).
• If testing later: limit fluids 2–3 hours prior; avoid excessive intake.
• High-sensitivity tests (10 mIU/mL) tolerate more dilution.

Myth Busting

• "Tea causes false negative"—false. Dilution does.
• "Hold urine 4 hours"—reasonable alternative to first-morning.

Hydration is healthy; just time your test for concentrated urine.