For Healthcare Professionals Only
Micronutrient deficiencies are far more common than previously assumed, even across developed countries, and emerging global data highlights their direct relevance to fertility and pregnancy outcomes. With inadequate intake of essential nutrients such as iodine, iron, calcium and vitamin E affecting billions worldwide, these hidden gaps may silently impair reproductive health, increase pregnancy risks, and influence both maternal and fetal development. Addressing micronutrient adequacy should be a core component of modern preconception and pregnancy care.
For years, it has been widely assumed that micronutrient deficiencies are uncommon in developed countries. However, new global research suggests the opposite- and the implications for fertility, pregnancy care, and women’s health are significant.
The Hidden Scale of Global Micronutrient Deficiencies
A comprehensive global analysis (PMID: 39218000) assessed dietary patterns across 185 countries, providing the first worldwide estimates of inadequate intake for 15 critical micronutrients. The findings were striking:
Global Prevalence of Key Micronutrient Gaps
- Iodine: 68% of the world population- over 5 billion people - consume insufficient iodine, a nutrient crucial for thyroid function and fetal brain development.
- Vitamin E: 67% have inadequate intake of this fertility-supportive antioxidant.
- Calcium: 66% are not meeting daily needs, affecting bone health and increasing risk of pregnancy-related hypertensive disorders.
- Iron: More than 4 billion people (65%) are iron deficient. Women and children are disproportionately affected.
- Across many regions, women consistently demonstrate lower intake of iodine, B12, iron, selenium, vitamin E, riboflavin, calcium, and folate compared to men.
These findings highlight a reality that many practitioners observe clinically: micronutrient adequacy is not guaranteed by geography or socioeconomic status.
Why This Matters for Fertility & Pregnancy
Why Micronutrient Status Matters for Fertility and Pregnancy
Many of the nutrients identified as inadequate play direct, documented roles in:
- Ovulation
- Menstrual regularity
- Thyroid function
- Egg quality
- Sperm quality
- Placental development
- Fetal brain, bone, and nervous system development
- Reducing pregnancy complications (pre-eclampsia, anaemia, low birth weight, preterm birth)
Subclinical deficiencies, even without overt symptoms, may impair fertility or increase pregnancy risks.
Clinical Implications for Preconception and Pregnancy Care
Practitioners working in preconception and pregnancy care should consider:
- Increased nutrient demands during pregnancy
- Dietary restrictions (intentional or due to nausea/aversions)
- Reduced intake of animal foods
- Lower nutrient density of modern food systems
- Poor iodine and selenium content in soils in certain regions
Nutritional Assessment and Dietary Guidance
- Assess dietary patterns thoroughly food-frequency questionnaires alone may miss nutrient gaps. Explore variety, food quality, and intake patterns over time.
- Educate patients on nutrient-dense foods Eggs, seafood, dairy, nuts/seeds, red meat, and iodine-rich foods (e.g., dairy, fish, eggs) should be part of fertility and prenatal nutrition guidance when appropriate.
- Prioritise iron, iodine, folate, B12, vitamin D, choline, magnesium and omega-3 fats These are consistently low in women of reproductive age globally.
Supplements should be seen as an insurance policy, not a replacement for real food, but for many women, they are essential for closing nutrient gaps.
Key Takeaway for Practitioners
Micronutrient insufficiency is widespread, even in developed countries, and it affects the very nutrients most closely linked with fertility and optimal pregnancy outcomes. Integrating targeted dietary guidance and quality supplementation into clinical care can meaningfully improve outcomes for women and their babies.
References:
Passarelli, S., Free, C.M., Shepon, A., Beal, T., Batis, C. & Golden, C.D. 2024, ‘Global estimation of dietary micronutrient inadequacies: a modelling analysis’, The Lancet Global Health, vol. 12, no. 10, pp. e1590–e1599. [thelancet.com]
Global Alliance for Improved Nutrition (GAIN) 2024, Billions worldwide consume inadequate levels of micronutrients critical to human health, GAIN Press Release, 29 August. [gainhealth.org]
Harvard T.H. Chan School of Public Health 2024, Billions worldwide deficient in essential micronutrients, Harvard Gazette, 29 August. [news.harvard.edu]
Happiest Health 2024, ‘Over half of global population has inadequate micronutrient intake’, 28 October. [happiesthealth.com]
Beal, T., Massiot, E., Arsenault, J., Smith, M. & Hijmans, R. 2017, ‘Global trends in dietary micronutrient supplies and estimated prevalence of inadequate intakes’, PLoS One, vol. 12, no. 4, e0175554. [pmc.ncbi.nlm.nih.gov]
Frequently Asked Questions
-
Are micronutrient deficiencies common in developed countries?
Yes. Global research across 185 countries shows that micronutrient deficiencies are widespread, even in developed regions, challenging the assumption that geography or socioeconomic status ensures adequacy.
-
Which micronutrients are most commonly deficient worldwide?
The most prevalent deficiencies include iodine, vitamin E, calcium and iron, with women consistently showing lower intake of several key nutrients linked to fertility and pregnancy.
-
How do micronutrient deficiencies affect fertility?
Many of the nutrients identified play direct roles in ovulation, menstrual regularity, egg and sperm quality, thyroid function and placental development.
-
Can subclinical deficiencies impact pregnancy outcomes?
Yes. Even without obvious symptoms, insufficient micronutrient intake can increase the risk of pregnancy complications such as anaemia, pre-eclampsia, low birth weight and preterm birth.
-
Are supplements necessary during preconception and pregnancy?
While real food should remain the foundation, supplementation is often essential for women to meet increased nutrient demands and close persistent dietary gaps.
