How Women Can Improve Their Fertility & Hormone Health | Dr. Natalie Crawford

TL;DR

Dr. Natalie Crawford explains how fertility is a key health marker and shares actionable lifestyle, supplement, and hormonal strategies to improve female reproductive longevity.

Key Points

• 1.Fertility is a whole-body health marker, not just a reproductive metric. Women with infertility have increased rates of metabolic syndrome, cancer, heart attack, stroke, and early death — not because infertility causes these, but because it's often the first sign of chronic inflammation or insulin resistance.
• 2.Women are born with all their eggs and lose them continuously throughout life. Peak egg count is 6–7 million at five months in utero, dropping to 1–2 million at birth, 500,000 at first period, and declining further each month proportional to remaining supply.
• 3.Egg quality is defined by genetic normality and mitochondrial competency, and cannot be directly tested. Chromosomes are held in metaphase of meiosis 2 for decades, and the longer they're held, the more likely errors occur — explaining why older eggs produce more chromosomal abnormalities.
• 4.Metabolic health directly damages egg quality through oxidative stress and mitochondrial dysfunction. Chronic inflammation, insulin resistance, and obesity damage meiotic spindles holding chromosomes apart, compounding age-related egg quality decline beyond just tincture of time.
• 5.Natural fertility drops sharply with age using precise monthly probability figures. At 30: 20% chance per cycle; at 35–36: 11–12%; at 38: 5%; at 40+: 3% — though none of these numbers are zero.
• 6.Women who previously gave birth show a protective fertility benefit up to age 37. Data from the 'Time to Conceive' cohort study showed prior-birth women maintained 18–20% monthly conception probability until 37, then dropped — but secondary infertility is still real and underacknowledged.
• 7.The current infertility definition forces couples to fail before any investigation begins. By definition, infertility requires 12 months of failed attempts before testing; yet 72% of fertile couples conceive in the first six months, meaning the other 13% wait needlessly without screening.
• 8.Microplastics accumulate in the ovary and endocrine-disrupting chemicals worsen IVF outcomes. Population-based cohort studies link plastic-associated chemicals to lower live birth rates and longer time to pregnancy; reducing plastic exposure is one lever in the broader inflammatory burden framework.
• 9.AMH (anti-Müllerian hormone) testing is a critical but underutilized fertility screening tool. It measures egg quantity (not quality) and provides actionable data about ovarian reserve that can shape a woman's reproductive planning — anyone who wants future children should request this test.
• 10.Menopause is defined as 12 consecutive months without a period, but this definition is clinically problematic. Ovarian failure can precede the diagnosis by years; women suffer through the perimenopausal transition — which can last 5–10 years — without access to hormone therapy under current standards.
• 11.Hormone replacement therapy for women is becoming recognized as cardioprotective, neuroprotective, and bone-protective. Estrogen reduces Alzheimer's risk and cardiovascular risk; Dr. Crawford advocates starting HRT during perimenopause rather than waiting for full menopause to minimize the 12-month estrogen-free gap.
• 12.Progesterone and testosterone each play distinct roles in hormone replacement beyond estrogen alone. Some perimenopausal patients feel well on progesterone alone; testosterone is typically added last and only when estrogen replacement doesn't fully resolve symptoms, given estrogen-testosterone interconversion.
• 13.Chronic inflammation from autoimmune disease, endometriosis, and lifestyle factors may accelerate ovarian aging. Women with premature ovarian insufficiency show elevated inflammatory markers and fibrosis inside the ovary; treating conditions like Hashimoto's early and adopting anti-inflammatory habits likely extends ovarian lifespan.
• 14.After two pregnancy losses, evaluation is medically warranted but historically withheld. Standard workup includes blood tests, semen analysis, sperm fragmentation testing, and uterine/tubal evaluation; Dr. Crawford personally was told she needed a third loss before tests would be ordered — a practice she strongly condemns.
• 15.Dr. Crawford's four pregnancy losses and IVF journey fundamentally shaped her clinical philosophy and research focus. Her personal experience of being dismissed as a patient — even while training as a reproductive endocrinologist — drove her fellowship research on natural fertility epidemiology and her book 'The Fertility Formula.'