Malnutrition in Pregnant Women and its Association with Newborn Weight and Adiposity

Malnutrition is a comprehensive term that includes undernutrition, micronutrient-related imbalances, and overnutrition.¹ Nutritional imbalances in either direction have a significant detrimental effect on morbidity and mortality. Undernutrition and micronutrient deficiency result in physical wasting, stunting, and improper growth and development, particularly in young children. Overnutrition can result in excessive weight gain, obesity, and diet or lifestyle-related non-communicable diseases (NCDs) in adolescents and adulthood.^1-3 Therefore, the double burden of malnutrition is a major public health concern worldwide. Further, owing to large socio-economic disparities within low-and middle-income countries including India, the health systems have to prioritize addressing maternal and child undernutrition in reducing the burden of obesity and related NCDs.^4-6

Child and maternal malnutrition are responsible for 17·3% (16·3–18·2) of the total disability-adjusted life years (DALYs) across all ages. In India, 68.2% of under-five deaths in children and 67.1% of total DALYs are attributable to malnutrition, which is the leading risk factor for health loss for all ages.4 In 2017, India had one-fourth of the total global DALYs attributable to child and maternal malnutrition.⁴ Similarly, the DALY rate attributable to malnutrition in children under five years was 50 627 (47 301–54 199) in 2017. The highest proportion of malnutrition DALYs in under-5 was due to low birth weight and short for gestational age 43.6 (95% UI 41.8 to 45.2), followed by child growth failure (20·7%, 19·0–22·5). The highest contribution to DALYs resulting in child growth failure was from child wasting (19·0%, 95% UI 16·2–21·2), followed by child underweight (7.16% 95% UI 6.01 to 8.97) and child stunting (4.09%, 95% UI 1.88 to 7.44).⁴ While undernutrition has been a historical concern, overnutrition is steadily rising. The National Family Health Survey (NFHS)-5 data of 2019- 21 shows, 35.5% of children aged under five years were stunted, 19.3 were wasted, 32.1 % were underweight,⁴ and the number of overweight children increased from 2.1 per cent in National Family Health Survey (NFHS)-4 to 3.4 per cent.⁵

Children in low- and middle-income countries (LMICs), especially girls, are prone to inadequate nutrition throughout their life course. The disparity in nutritional status affects trans-generally, in a vicious perpetual cycle right from the fetal stage to infancy. As they grow up, these low-nutrient foods, coupled with low physical activity and continuous access to digital media, increase childhood obesity while undernutrition issues remain unresolved. The recentComprehensive National Nutrition Survey (CCNS) survey across the country reported that 35% of children aged 5 to 9 years are underweight. In comparison, 8% had high adiposity measured through subscapular skinfold thickness (SSFT) for their age.⁶ The malnourishment of the mother and child is closely linked. It is well known that maternal weight and overall nutritional and health status impact the neonate’s health. In cases where the mother is chronically undernourished at the time of conception and through pregnancy, there is an increased risk of adverse birth outcomes such as intrauterine growth restriction and low birth weight (<2500 gm).^7-9

On the other hand, excessive gestational weight gain, maternal obesity, and related pregnancy complications such as gestational diabetes mellitus (GDM) are associated with the birth of large for gestational age (LGA) babies, as indicated by high body mass index and adiposity.^10-13 Infants of mothers with increased prepregnancy weight and weight gain in pregnancy have a greater risk of macrosomia and adiposity. Adiposity was further related to increased infant blood pressure.¹⁴ Maternal obesity severely impacts a child’s growth and development; it increases the child’s risk of obesity, coronary heart disease, non-alcoholic fatty liver disease (NAFLD), and type 2 diabetes.^15,16 Gestational diabetes has a higher risk for newborn adiposity. This has been proven by the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study and several other investigations in the past too.¹⁷ Tint et al., have shown an association between maternal glycemia and neonatal abdominal adiposity.¹⁸ Several studies have shown that babies born to mothers with gestational diabetes mellitus (GDM), obesity, and high triglyceride levels are at risk of greater adiposity.^19,20

Further, recent studies have established that large for gestation-age (LGA) babies are predisposed to obesity in later stages of life.^21,22 Similarly, evidence suggests babies born with high BMI tend to be overweight during the growing years and adulthood.^23,24 Childhood obesity can greatly impact the child’s physical, emotional and social well-being. Overweight and obese children also are known to have psychosocial distress.

Globally, childhood obesity is increasing and reaching alarming proportions. The prevalence of overweight increased from 4.8% in 1990 to 5.9% in 2018.²⁵ The World Health Organization (WHO) estimated that 38 million children under five years were obese in 2019.²⁶ Once considered the problem of affluent countries, obesity is steadily gripping low- and middle-income countries (LMICs). The LMICs are burdened with a high incidence of cardiovascular diseases with increasing longevity. The catastrophic out-of-pocket expenditure is increasingly the major reason for impoverishment.

Interestingly, although most previous evidence indicated that low birth weight babies are at decreased risk of childhood and adult obesity,²⁷ some of the more recent findings have contradicted this notion. The biological mechanisms for this paradoxical association remain unclear. Still, some reports indicate that low birth weight babies may be at higher risk of obesity and diabetes in adulthood.²⁸

However, the adverse pregnancy outcome in the form of adiposity due to malnutrition in the mother is incomplete without studying the effect of undernutrition.²⁹ Earlier evidence has rendered a link between nutritional insults during pregnancy resulting in low birth weight and insulin resistance, glucose intolerance, and adiposity in adulthood. Various mechanisms have been proposed to understand fetal reprogramming. This involves increased oxidative stress, inflammation, alteration in circadian rhythm, increased activity of hypothalamicpituitary-adrenal (HPA), and epigenetic alterations, among several others.^30,31

A woman’s height and leg length are direct markers of her nutritional status as a child. Leg length is a reliable marker of maternal undernutrition due to the cephalo-caudal gradient in growth from birth until puberty. Those individuals that receive adequate nutrition in childhood have relatively long legs. National Health and Nutrition Examination Survey (NHANES) study has shown that women with short legs had greater body fat percentages, insulin resistance, and a higher prevalence of type 2 diabetes mellitus.³² Among South African girls, shorter relative leg length was independently associated with increased waist circumference.³³ Short stature has been associated with overweight and child mortality, anaemia, stunting, and growth retardation.^34,35 Maternal height and leg length’s positive association with neonatal birthweight was proven in previous studies;^36-38 however, more research is needed concerning adiposity. Pune children’s study has established the positive association of adult leg length with birth weight and regional lean mass measurements. Leg length was also inversely related to body mass index.

Shorter leg length exposes an individual to a greater risk of metabolic diseases.³⁹ Caerphilly study showed that leg length was related to insulin resistance and high Homeostasis Model Assessment (HOMA) scores among men.⁴⁰ The PROMISE study showed that leg length was related to insulin sensitivity index and β- cell function. In a Brazilian cohort, a one-unit decrease in relative leg-length Z score was associated with a 12% higher prevalence of diabetes in men and women.⁴¹ Many epidemiologic studies have proven that women with GDM have shorter leg lengths.^42-45 In the Pune Maternal Nutrition study, high glucose values during pregnancy were traceable to higher glucose values from the age of six years. Hence, GDM is no longer a random event but has its antecedents from childhood days.⁴⁶

The ‘thrifty phenotype’ hypothesis proposes that poor nutrition of mothers during gestation leads to the programming of metabolism in the fetus, which results in obesity in later stages. This is particularly true if the child goes on to receive a high-calorie diet. Poor nutrition in the mother’s early life results in low birth weight, predisposing her offspring to increased cardiovascular disease risk in later life. Studies in lab animals have strengthened the thrifty phenotype hypothesis that suggests that a mother’s undernutrition during gestation increases the metabolism of adipocytes and fat mass of the fetus, which results in obesity in later stages.⁴⁷ 

Along with the ongoing battle with undernutrition, India is facing a rising epidemic of obesity and diabetes. It is important to study how these factors could be interrelated. It is imperative to curb undernutrition to handle the burgeoning problem of obesity in the country. Nutrition calls for a whole of government and whole of community approach. It is important to bring awareness among the community about breastfeeding, avoiding junk food and going for healthy local and seasonal food, using clean water and sanitation. Various departments like agriculture, women and child development, water and sanitation, department of education, information technology, media and communication will have to converge to manage malnutrition in the country. It is very important that adequate finance, manpower, technology and resources are designated to reach the nutrition targets by 2030.

Conflict of interest

None