In the late 1950s, epidemiologists believed that the fetus was a “perfect parasite” and that it survived at the mother’s expense when nutrients were in short supply. The placenta was regarded as a “perfect filter, protecting the fetus from harmful substances in the mother’s body and letting through helpful ones”. Women were advised not to gain too much weight during pregnancy, which would lead to a difficult labour.

A large per cent of deliveries in Pakistan take place at home under the supervision of untrained dai or midwives. This practice of restricting weight gain still survives in Pakistan, where midwives advise women not to gain too much weight for fear of obstructed labour.

In 1992, David J. Barker, a British physician and epidemiologist, stated a hypothesis that inadequate nutrition in utero ‘programmes’ the fetus to have metabolic characteristics that can lead to future diseases. Mr Barker said that a fetus starved in the uterus is more likely to become overweight as an adult and therefore more likely to suffer from diseases associated with obesity, such as cardiovascular disease, hypertension, and diabetes.

The Fetal Origins of Disease hypothesis states that: The effects of fetal malnutrition last into adulthood. The health effects can remain latent for many years and emerge as non-communicable diseases in middle age.This is due to a specific biological mechanism, fetal “programming,” possibly through the effects of the fetal environment on the epigenome.

If a baby starves in the uterus, the health effects can remain latent and emerge as low test scores in school or diseases in middle age

The epigenome can be conceived of as a series of switches that cause various parts of the genome to be expressed — or not. The period while the fetus is in utero may be particularly important for setting these switches.

The fetal origins hypothesis has implications for individual decisions and policy alike, suggesting for example, that the optimum time to intervene to improve children’s life chances is before they are born and perhaps before mothers even realise that they are pregnant.

According to the United Nations International Children’s Emergency Fund, birth weight is a good indicator of not only the mother’s health and nutritional status but also of the newborn’s development.

In Pakistan, 32pc of the babies born are of low birthweight, i.e. less than 2500 grams — the second highest recorded rate in the world. According to the National Nutrition Survey (2018), stunting (low height for age) for under-fives is around 40pc nationally, Economists have expanded on this hypothesis, investigating a broader range of fetal shocks and circumstances, and have found a wealth of later-life impacts on outcomes, including test scores, educational attainment and income along with health. In the process, they provided some of the most credible observational evidence supporting the hypothesis. The magnitude of the impacts is generally large. Thus, the fetal origins hypothesis has not only survived contact with economics but has flourished.

The World Health Organisation (WHO) stated that in the developing regions, some of the most formidable enemies of health are joining forces with the allies of poverty to impose a double burden of disease, disability and premature death in many millions of people.

Almost half of the adult disease burden in South Asia is attributable to non-communicable diseases. Pakistan is faced with a double burden of disease — undernutrition of mother, fetus and child and non-communicable disease in young adults.

Pakistan is among the top 10 countries for high numbers of people with diabetes and a third of Pakistanis aged more than 45 years have hypertension.

Several surveys of risk factors conducted across South Asian countries have shown high and rising rates of overweight, central obesity, diabetes, high blood pressure and dyslipidaemia in urban populations. Such trends also exist in rural populations but are lower in magnitude.

Therefore, to stem the tide of increasing non-communicable diseases Pakistan will have to have a two-pronged approach. Improve mother and child nutrition and health and address the environmental factors that are the major determinants of almost all non-communicable diseases. WHO identifies four main risk factors — unhealthy diets, physical inactivity, tobacco use and the harmful use of alcohol.

The author taught nutrition at Aga Khan University for 25 years

Published in Dawn, The Business and Finance Weekly, September 12th, 2022