Fertility, Sperm Health, and Nutrition Before and During Pregnancy | Dr Federica Amati

What It Covers

Nutritionist Federica Amati outlines the science behind the "first 1,000 days" — from 90 days preconception through a child's second birthday — explaining how parental nutrition, sperm and egg quality, and the in-utero environment set the biological foundation for a child's lifelong metabolic, cognitive, and cardiovascular health outcomes.

Key Questions Answered

• •The 90-Day Preconception Window: Both sperm and egg quality respond to lifestyle changes within roughly 90 days. Men produce entirely new sperm in this cycle, making diet, alcohol elimination, and heat avoidance (saunas, hot baths, tight cycling shorts) directly actionable. Women benefit from folate supplementation, adequate food intake, and iron status optimization. Couples can align their 90-day preparation simultaneously, measurably improving DNA fragmentation rates and ovulation quality.
• •Sperm Heat Exposure: Even 20 minutes of scrotal heat exposure — from laptops, hot baths, or tight athletic wear — can measurably reduce sperm count and structure for up to three to four months. Men trying to conceive should eliminate regular sauna use and avoid heat sources near the groin during the full 90-day preconception window, as sperm recovery to baseline can take the entire cycle length.
• •Paternal Health Affects Offspring Brain Development: Paternal metabolic health preconception influences offspring neurocognitive outcomes differently than maternal health. Studies link paternal diet quality and BMI to child neurodevelopmental markers, including autism spectrum disorder risk. Sperm DNA also plays a direct role in placenta formation, meaning a father's nutritional status shapes the in-utero environment throughout the entire pregnancy, not just at the moment of conception.
• •Maternal Metabolic Status Shapes Offspring Appetite Wiring: Women with leptin resistance during pregnancy give birth to infants with structurally different hypothalami — specifically, babies show heightened hunger-cue reactivity and reduced satiety signaling. This increases the child's lifetime obesity risk. Separately, gestational diabetes raises the likelihood of large-for-gestational-age births and elevates the child's future type 2 diabetes risk, making preconception metabolic health a direct lever for the next generation.
• •GLP-1 Medications Restore Fertility — Creating an Unplanned Pregnancy Risk: GLP-1 agonists reduce excess adiposity, which raises testosterone in men and restores ovulatory cycles in women with PCOS. Many patients are not informed of this fertility restoration effect. Current guidelines recommend stopping GLP-1 medications 90 days before attempting conception. Additionally, GLP-1s slow gastric emptying, which may reduce oral contraceptive absorption, making alternative contraception methods advisable during treatment.
• •Protein Supplementation in Pregnancy Is Counterproductive: Pregnant women need 1.3–1.6 grams of protein per kilogram of body weight, but high-dose protein supplements are associated with increased intrauterine growth restriction risk, resulting in smaller-than-normal birth weight. Protein needs are better met through whole food combinations — legumes paired with whole grains provide a complete essential amino acid profile alongside fiber and micronutrients. Increased caloric and protein needs only become significant in the third trimester.