Pregnancy: An Extraordinary Biological Marathon

Hi I’m Sammy,

Your Good Farm in-house nutritionist. Here to bring you essential information on nutrition, diet and permaculture gardening - in a bite size, easy to understand, science-backed way.

Let's talk about... PREGNANCY! Something I've just been through for the second time in my life.

Pregnancy: An Extraordinary Biological Marathon

Pregnancy is one of the most physiologically demanding events the human body will ever undertake, and yet it is often treated as routine.

It is also one of the most extraordinary expressions of human biology. In just a few months, the body coordinates growth, protection, and connection with remarkable precision, reshaping metabolism, immune function, the brain, and even a woman’s sense of self.

In less than a year, the body builds an entirely new organ, expands blood volume by nearly 50 per cent, and grows another human being, cell by cell.

Yet culturally, pregnancy is often framed as something the body should simply cope with. Preparation is minimal, support may be inconsistent, and recovery is often rushed. Fatigue, nausea, anxiety, iron depletion, and blood sugar instability are frequently normalised, despite reflecting measurable biological load.

Pregnancy is an active state of sustained, high-cost adaptation. Like training for a marathon, it requires preparation, nourishment, and support, not just endurance.

Sustained Physiological Change

Pregnancy places continuous demand on every major physiological system. In many ways, it resembles prolonged physiological stress, except that it continues uninterrupted for many months and is directed toward growth rather than survival alone.

Specifically, the body is:
• Increasing blood volume by up to 50 per cent
• Growing a temporary but highly active organ, the placenta
• Supporting rapid cell division and tissue growth
• Reprogramming hormones to prioritise another life
• Adjusting metabolism to ensure a continuous energy supply
• Reshaping the brain to support bonding, caregiving, and vigilance

While elite athletes deliberately train to tolerate far smaller degrees of sustained physiological load, pregnant women are often expected to maintain work, family responsibilities, and daily life while meeting these demands, frequently without adequate nutritional foundations.

This mismatch between biological demand and practical support is where many pregnancy challenges begin.

Blood Volume, Oxygen, and Nutrient Demand

To improve oxygen delivery, endurance training increases blood volume gradually. In pregnancy, blood volume expands rapidly to support oxygen and nutrient delivery to the developing baby.

This expansion places increased demand on:
• Iron for oxygen transport
• Protein for plasma and tissue synthesis
• B vitamins for cellular energy metabolism
• Electrolytes for cardiovascular stability

When intake, absorption, or utilisation falls short, the body compensates by drawing on existing stores. Fatigue, breathlessness, and dizziness are not signs of poor resilience or weakness. They are signals that the system is operating under sustained strain.

Growing a New Organ While Sustaining Life

The placenta is one of the most metabolically active organs in the human body. Acting as lungs, kidneys, liver, and endocrine system for the developing baby, it regulates nutrient transfer, produces hormones, and manages waste continuously throughout pregnancy.

This work depends on a steady supply of:
• Amino acids from protein
• Fats and cholesterol for hormone production
• Minerals such as zinc, iodine, selenium, iron, magnesium, and calcium
• Key vitamins including A, D, C, K2, and B vitamins such as folate and B12
• Choline and other cofactors essential for brain development and methylation

Pregnancy is not about avoiding deficiencies. It is about meeting ongoing demand with nutrient-dense, bioavailable foods that support both maternal physiology and optimal foetal development.

The Pregnant Brain Is Adapting

Cognitive and emotional changes during pregnancy are often framed as decline, but neuroimaging and longitudinal research tell a different story. Pregnancy reshapes brain regions involved in:

• Emotional processing
• Threat detection and protection
• Empathy and bonding
• Sensory awareness

These adaptations support caregiving and attachment. Neurological change is energetically demanding. The brain relies on stable blood sugar, adequate fats, especially DHA (found in wild-caught salmon, sardines, and cod liver oil), and key micronutrients such as iron, choline, and iodine to adapt effectively.

When fuel supply is inconsistent, this process becomes more difficult, contributing to cognitive fatigue and emotional overwhelm.

Metabolic Stress, Blood Sugar Stability, and Early Development

As pregnancy progresses, insulin resistance naturally increases. This is a hormonally mediated adaptation that ensures a continuous glucose supply for the growing baby.

How well this transition is tolerated depends strongly on metabolic health before conception. Entering pregnancy with blood sugar instability, inflammation, or nutrient depletion increases physiological strain.

Research within the Developmental Origins of Health and Disease (DOHaD) framework shows that the metabolic environment in early pregnancy helps shape a child’s metabolism, appetite regulation, and stress response. Stable blood sugar before and during pregnancy supports maternal energy and wellbeing while shaping the child’s long-term metabolic health.

Preparation Was Once Central to Pregnancy and Child Health

In many traditional cultures, pregnancy was not treated as an event that began at conception. Preparation was understood to shape the health of the next generation well before pregnancy occurred.

Women, and often men, were supported months or years before conception with specific foods, rest, and community care. Nutrient-dense foods such as organ meats, seafood, bone broths, and animal fats from healthy, pasture-raised animals were deliberately prioritised for those preparing to conceive.

Weston A. Price documented how butterfat from cows grazing on mineral-dense spring pastures was reserved for women of childbearing age. These foods were recognised as essential for fertility, pregnancy resilience, and child health.

This ancestral emphasis reflects what we now understand about egg and sperm quality, early embryonic development, and epigenetic programming. While pregnancy draws heavily on nutritional stores, many foundations for growth are laid well before the first trimester.

Modern prenatal care often begins after conception. By this time, early developmental processes are already underway, however, pregnancy remains a period of remarkable adaptability and opportunity.

Matrescence: The Becoming of a Mother

Anthropologists and maternal health researchers use the term matrescence to describe the transition into motherhood, a developmental stage as profound as adolescence. The term was first coined in the 1970s by medical anthropologist Dana Raphael to articulate the physical, psychological and social shifts that accompany becoming a mother. In recent years, it has been revived through the work of writers such as Lucy Jones and educators including Jane Hardwicke Collings, helping to bring the concept into contemporary maternal discourse.

Matrescence recognises that pregnancy and early motherhood reshape identity, neurology, emotional processing and relationships, not just the body.

Women are often expected to emerge from pregnancy unchanged apart from a baby in their arms. They are assumed to be emotionally competent, productive and self-sacrificing while navigating one of the most significant transitions of their lives.

When the scale of this change is unacknowledged, normal adaptive responses can be misinterpreted as personal failure or pathology. Naming matrescence restores context. It reminds us that change is not a sign of weakness but evidence of a system reorganising itself for caregiving, protection and connection.

Notably, a recent piece in The New York Times highlighted the cultural lag in language around motherhood, observing that while colloquial expressions like “IDGAF” have secured a place in the dictionary, matrescence still struggles for the same formal recognition, perhaps reflecting how slowly our language evolves to catch up with the realities of women’s lived experience.

Setting the Foundation for What Follows

This article, and the series that follows, is not designed to overwhelm, but to restore perspective and cultivate awe for the profound physiological, neurological and metabolic changes a woman’s body undertakes to bring new life into the world. Recognising the scale of this transition shifts expectations away from simply coping and toward intentional preparation, nourishment and support.

With knowledge comes informed choice. We can influence nutrition, rest, blood sugar stability and recovery, while also acknowledging that not every aspect of pregnancy is within our control. Each pregnancy unfolds differently; sometimes the most important work is to adapt, surrender and support the body as circumstances require.

Our aim is to translate this understanding into realistic, food-first and compassionate practices that support women before, during and after pregnancy.

Love, Sammy.

Across this series, we will explore:

• How and why to optimise preconception care
• Practical ways to build and sustain nutritional reserves throughout pregnancy and the post-partum period
• Which nutrients matter most, and why form, timing and absorption are just as important as total intake
• Our nutritionist Sammy’s personal experience navigating a high-risk pregnancy with placenta praevia, and how she prepared for a planned caesarean birth after a previous low-intervention vaginal birth
• Why post-partum recovery extends well beyond six weeks, and why it deserves deeper nourishment, rest and intentional support
• A nutritionist’s guide to short and prolonged hospital stays; what to pack, how to maintain nourishment, and how to support recovery in a clinical environment.

Reference List

1.   GLOWM. Maternal Physiological Changes in Pregnancy — detailed overview of cardiovascular and blood volume changes, including up to ~50 % increase in blood volume during pregnancy. Glowm

2.   Herrera E. Metabolic Physiology in Pregnancy — review summarising the unique metabolic adaptations of pregnancy, including shifts in insulin sensitivity and fuel partitioning between mother and fetus. PubMed

3.   Catalano PM, Hauguel-de Mouzon S. Endocrine and Metabolic Adaptations to Pregnancy: Impact of Obesity — review of endocrine regulation of maternal metabolism and the diabetogenic nature of pregnancy (insulin resistance). PubMed

4.   Stern C et al. Placental Endocrine Activity: Adaptation and Disruption of Maternal Glucose Metabolism in Pregnancy — comprehensive review of how the placenta drives insulin resistance and adaptations in maternal glucose metabolism, and how extreme changes can contribute to gestational diabetes. PMC

5.   Gaccioli F, Powell TL, Jansson T. Placental Transport in Response to Altered Maternal Nutrition — review explaining how placental transporters respond to maternal nutrition, linking maternal diet to fetal nutrient supply and growth. Cambridge University Press & Assessment

6.   Bowe JE. The Pancreas and the Placenta: Understanding Gestational Diabetes and Why Some Islets Fail to Cope — mechanistic overview of β-cell adaptations and placental hormone signalling in pregnancy. Portland Press

7.   Chavatte-Palmer P et al. Diet before and during Pregnancy and Offspring Health: The Importance of Animal Models and What Can Be Learned from Them — DOHaD review showing how maternal nutritional environments influence offspring long-term health and metabolism. PMC

8.   Gluckman PD, Hanson MA, Cooper C, Thornburg KL. Effect of In Utero and Early-Life Conditions on Adult Health and Disease — seminal work describing the DOHaD hypothesis and how early maternal environments program lifelong risk of disease. Cambridge University Press & Assessment

9.   Hanson MA, Godfrey KM, Lillycrop KA, Burdge GC, Gluckman PD. Developmental Origins of Health and Disease: Current Knowledge and Potential Mechanisms — review on how maternal under- and over-nutrition and stress hormones influence fetal programming and later disease risk. OUP Academic

10.                Yajnik CS, Deshmukh US. Maternal Nutrition, Intrauterine Programming and Consequential Risks in the Offspring — classic DOHaD article linking maternal nutrition and risk of later metabolic disease in offspring. PubMed

11.                Thompson MD, DeBosch BJ. Maternal Fructose Diet-Induced Developmental Programming — modern review exploring diet-induced programming mechanisms and effects on offspring health. MDPI

12.                Stern C et al. (above) also functions as a key source describing the physiologic decline in insulin sensitivity in pregnancy and its placental mediation. PMC

13.                Additional physiology of the diabetogenic state of pregnancy is described in Catalano & Hauguel-de Mouzon’s metabolic adaptation work. PubMed