Written by Dr Karen Joash, Consultant Obstetrician and Gynaecologist and Co-Founder of PurerVita
When you are thinking about pregnancy, it is easy to focus on one question:
“How can I get pregnant?”
But there may be a better question:
“How can I create the healthiest possible biological environment before pregnancy begins?”
Pregnancy does not start with a positive pregnancy test. Long before implantation, your body is supporting follicle development, hormone signalling, mitochondrial energy production, immune balance, metabolism and the preparation of the endometrium.
This is the idea behind my Cellular Fertility Blueprint™: fertility is not controlled by one vitamin, one hormone or one supplement. It reflects an interconnected biological system.
The goal is not perfection. It is to improve the environment in which conception, implantation and early development occur.
Why preconception health matters
The months before conception offer an important window in which nutrition, metabolic health, smoking, alcohol, medication, physical activity and existing medical conditions can be addressed.
UK guidance recommends starting 400 micrograms of folic acid daily, ideally around three months before conception, and continuing until 12 weeks of pregnancy. Vitamin D supplementation is also recommended in pregnancy, particularly during months when sunlight is inadequate.
But preconception optimisation goes beyond folic acid.
Think of fertility as depending on four fundamental cellular functions:
Energy. Protection. Communication. Adaptation.
1. Energy: can the cell do the work required?
Egg maturation, fertilisation, embryo development and implantation are energy-intensive processes.
Mitochondria produce most of the energy used by cells. Oocytes contain particularly large numbers of mitochondria because early embryo development requires substantial energy.
Age is an important determinant of egg quality and cannot be reversed by lifestyle or supplements. However, metabolic health, nutrient sufficiency, smoking, oxidative stress and general health may influence the biological environment surrounding the developing follicle.
This is why I prefer the phrase supporting egg health rather than promising to “improve egg quality”.
2. Protection: reducing unnecessary oxidative stress
Reactive oxygen species are part of normal cellular signalling. The aim is not to eliminate them.
Problems arise when oxidative stress overwhelms the body’s antioxidant defence systems. Factors that can contribute include:
- Smoking
- Significant air pollution exposure
- Metabolic dysfunction
- Poor diet
- Excessive alcohol
- Chronic inflammation
- Some environmental chemical exposures
The practical response is not an extreme “detox”. It is a lower-exposure, nutrient-rich lifestyle.
3. Communication: hormones, nutrients and cellular signalling
Reproduction depends on extraordinarily complex communication between the brain, ovaries, thyroid, endometrium, immune system and developing embryo.
This is one reason that preconception care should include identifying conditions such as thyroid disease, diabetes, insulin resistance, PCOS, anaemia and significant nutritional deficiencies.
It is also where nutrients such as folate, choline, iodine, iron, vitamin B12 and vitamin D become biologically important.
Choline deserves more attention
Choline contributes to cell membranes, methylation pathways and fetal neurological development.
A 2024 systematic review found that only around 11% of pregnant women met recommended choline intake, while higher maternal choline status was associated with lower odds of adverse pregnancy outcomes. That does not prove that choline supplementation prevents those outcomes, but it does reinforce how overlooked this nutrient remains.
Food sources include eggs, fish, meat, dairy, soya and some legumes.
4. Adaptation: metabolic health matters
Pregnancy requires enormous metabolic adaptation. Insulin sensitivity, vascular function and maternal energy metabolism all change during pregnancy.
This means that the preconception period is an opportunity to optimise weight, blood pressure, glucose regulation, cardiovascular fitness and dietary quality.
A Mediterranean-style dietary pattern, rich in vegetables, fruit, legumes, whole grains, nuts, olive oil and fish, has some of the strongest evidence among dietary patterns in reproductive and pregnancy health.
Randomised and observational evidence suggests benefits for pregnancy outcomes including gestational diabetes and preterm birth, although evidence specifically for improving fertility remains less certain.
Food pattern before pills.
Supplements can fill gaps. They should not compensate for a poor diet.
The seven areas I would optimise before pregnancy
1. Nutrition
Build meals around vegetables, protein, healthy fats and fibre-rich carbohydrate.
Prioritise:
- Leafy vegetables
- Legumes
- Eggs
- Oily fish
- Berries and colourful fruit
- Whole grains
- Nuts and seeds
- Extra-virgin olive oil
- Adequate protein
The aim is nutritional sufficiency rather than restriction.
2. Folate
Take 400 micrograms folic acid daily when trying to conceive and through the first 12 weeks unless you have been advised to take a higher prescription dose.
Some women require 5 mg, for example because of particular medical conditions, medicines or previous or family history of neural-tube defects.
3. Vitamin D
Vitamin D is important for bone, immune and reproductive biology.
The NHS recommends 10 micrograms, or 400 IU, daily during pregnancy, particularly during autumn and winter, with year-round supplementation advised for people at increased risk of deficiency.
Women with known deficiency may require individual assessment rather than simply increasing supplements themselves.
4. Choline
Check whether your diet provides meaningful amounts of choline. This is particularly relevant for women who eat few eggs, fish, meat or dairy foods.
Choline is likely to become a much bigger part of the pregnancy-nutrition conversation over the next decade.
5. Movement
Regular activity can improve insulin sensitivity, cardiovascular health, sleep and psychological wellbeing. The objective is not punishing exercise.
Think: walking, resistance training, aerobic fitness and movement throughout the day.
6. Sleep and circadian health
Sleep is not simply rest. It influences glucose regulation, appetite hormones, cortisol, immune function and mental health.
Poor sleep in pregnancy is consistently associated with adverse metabolic and psychological outcomes, although association does not prove that improving sleep alone prevents those outcomes.
Before pregnancy, aim for regular sleep and wake times, morning daylight exposure and reduced bright light late at night.
7. Environmental exposures
You cannot live in a toxin-free world. Nor do you need to.
But it is reasonable to reduce avoidable exposure to:
- Tobacco smoke
- Excessive air pollution
- Unnecessary pesticides
- Phthalates and some endocrine-disrupting chemicals
- Heating food in plastic
- Heavily fragranced products when alternatives are available
This is risk reduction, not fear.
What about fertility supplements?
This is where personalised care matters.
Some supplements have clear roles, folic acid is the obvious example. Others may be useful where dietary intake, blood tests or clinical circumstances indicate a need.
But more is not necessarily better. High-dose vitamins and minerals can interact with each other, medications and thyroid function. Vitamin A in retinol form, for example, should be avoided in high-dose pregnancy supplements.
The Cellular Fertility Blueprint™ therefore follows this order:
Food → lifestyle → identify deficiencies → targeted supplementation.
Not the other way around.
The preconception checklist
Ideally begin around three months before trying to conceive, although making healthy changes at any stage is worthwhile.
- Am I nutritionally replete?
- Is my metabolic health as good as it can reasonably be?
- Am I moving regularly?
- Am I sleeping well?
- Have thyroid disease, diabetes or other medical conditions been optimised?
- Have I stopped smoking?
- Am I taking folic acid?
- Are my medications pregnancy-compatible?
- Can I reduce unnecessary environmental exposures?
Pregnancy optimisation is not about guaranteeing pregnancy. It is about improving the conditions in which pregnancy begins.
My central message
Healthy pregnancy begins before conception, and it begins at cellular level.
That is the Cellular Fertility Blueprint™.
Frequently asked questions
How long before pregnancy should I start preparing?
Around three months is a useful practical starting point, although benefits can begin whenever you make positive changes.
Which vitamin is most important before pregnancy?
Folic acid has the clearest established preconception benefit. The NHS recommends 400 micrograms daily for most women trying to conceive.
Can supplements improve egg quality?
No supplement can reverse age-related changes in oocytes. Nutrients and lifestyle may support the biological environment surrounding follicle development, but claims to “rejuvenate” eggs should be treated cautiously.
What diet is best when trying to conceive?
A Mediterranean-style, minimally processed dietary pattern is a sensible evidence-based foundation.
Should my partner optimise his health too?
Absolutely. Fertility and pregnancy are biologically shared from conception.