NLM5008 Chap.5 Women's Preconception Health and Fertility
Women's Preconception Health and Fertility
The question behind the week
Week 3 asks how maternal, paternal and couple-based lifestyle before conception relates to fertility, including in couples using IVF.
The maternal reading, a 2025 review by the lead lecturer and colleagues, begins with demography: by 2050, 76% of countries are projected to have fertility rates under 2.1 children per woman, the level needed to replace each generation, and the share climbs to 97.1% of countries by 2100. It then asks what women's own health contributes, defining female fertility broadly as the capacity to conceive and achieve a live birth.
Five domains of evidence
The review sorts its evidence into lifestyle, socioeconomic status, environmental pollutants, body weight and metabolic health, and reproductive characteristics including lactation.
For physical activity, a meta-analysis of five cohorts found moderate activity linked to a 46% lower infertility risk than low activity, while very intense activity without enough energy intake can disturb hormones and impair fertility.
For diet, the Mediterranean pattern is linked to a lower risk of difficulty conceiving in the general population but shows no overall association in fertility-treatment cohorts; the WHO recommends 400 µg of folic acid a day from preconception to the twelfth week.
Findings that break the obvious assumption
Metabolic syndrome and insulin resistance were associated with lower fecundability across BMI categories, so normal weight is not the same as metabolic health.
Lifestyle programmes improved pregnancy and live birth rates in natural conception but showed no benefit among women having assisted reproduction. Each 10 µg/m³ rise in fine particles was associated with 20% higher odds of infertility.
Lactation lowers birth rates by spacing births, yet is also described as protective for the mother.
The gap the review names
Most evidence comes from White populations, and the Asia-Pacific is underrepresented across nearly every domain. Shift-work findings are more consistent but low in quality, sleep studies are mostly cross-sectional, and mental health burdens in the region are likely underestimated.
The authors call for holistic, multidisciplinary policy rather than single-factor advice.
What this chapter covers
- 01
Fertility decline and the replacement rate
- 02
Five domains shaping female fertility
- 03
Physical activity, energy balance and ovulation
- 04
Diet, folic acid, vitamin D and caffeine before conception
- 05
Metabolic health at every body weight
- 06
Pollution, lactation and the Asia-Pacific evidence gap
Worked example · free
Advising a patient whose weight looks reassuring
- 2Identify the metabolic concern and a change.
- 2Identify the energy balance concern and a change.
Key terms
- Total Fertility Rate
- The average number of children born per woman; 2.1 is the replacement level.
- Fecundability
- The probability of conceiving within one menstrual cycle.
- Energy Deficiency
- An imbalance in which energy spent exceeds energy eaten, disrupting reproductive hormones.
- Metabolic Syndrome
- A cluster of central obesity, raised blood pressure, glucose and lipids that raises cardiometabolic risk.
- Lactational Amenorrhea
- The suppression of ovulation during breastfeeding, which spaces births.
Women's Preconception Health and Fertility FAQ
Does physical activity help or harm female fertility?
Both, depending on dose and energy balance. Pooled cohort evidence links moderate activity to a lower infertility risk than low activity, while very intense activity without enough food can disrupt hormones and ovulation. The reading treats activity and diet as one system.
Is a normal BMI enough to rule out metabolic effects on fertility?
No. In a multi-ethnic Asian cohort, metabolic syndrome and insulin resistance were associated with lower fecundability across BMI categories, so a woman of normal weight can still carry a metabolic risk to conception.
Do weight-loss programmes help women having IVF?
The pooled trials in the reading found higher pregnancy and live birth rates in natural conception but no benefit among women undergoing assisted reproduction, so the evidence does not support them as a route to better IVF results on their own.
How does air pollution relate to fertility?
The reading reports that each 10 micrograms per cubic metre increase in fine particulate matter was associated with 20% higher odds of infertility and 11% lower fecundity, alongside links to early pregnancy loss.
Why does the review stress the Asia-Pacific region?
Because most evidence on women's health and fertility comes from White populations, leaving the region underrepresented in nearly every domain, even as its birth rates fall. Findings may not transfer directly to Asian women.
Assessment move
For each factor in the reading, write the direction, the population studied and how firm the evidence is. The quizzes on this reading tested direction and population more than numbers.
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