Research has pointed towards the importance of foetal health in child development. Assessing the impact of rainfall variability on child health, this column finds that exposure to drought in the womb increases the child’s likelihood of being underweight. It suggests that policies aimed at reducing child malnutrition need to start at the beginning of human life, that is, in the womb.
Prevalence of malnourished children in India is among the highest in the world. According to the Hunger and Malnutrition (HUNGaMA) Survey Report (2011)1 compiled and published by Naandi Foundation, 42% of children under five years of age in India are moderately or severely malnourished, a figure that is nearly double of that of Sub-Saharan Africa. Despite some progress in recent years, India is most likely going to miss the 2015 target of reducing child malnutrition to 28.6% as part of the Millennium Development Goals (MDGs).
Child health plays a crucial role in human capital development. Better nutrition and, thus, better health in early childhood improves not only health later in life, but also educational outcomes. The risk of malnutrition is especially high for children in rural areas, for children belonging to Scheduled Castes or Tribes (SC/ STs), for children from low-income families, and for children whose mothers have less or no schooling (Naandi Foundation 2011). For policymakers, it is important to understand not only the consequences of poor child health but also the causes.
Child malnutrition starts early in life with low birth weight being an important risk factor that indicates impaired foetal health. An assessment of foetal development can, thus, serve as an important link in understanding one channel of child malnutrition.
“Fetal Origins Hypothesis”
The importance of foetal conditions for the development of children has been documented by numerous researchers. One of the first to draw attention to the topic was David J. Barker, a British physician and epidemiologist (Barker 1990, 1995). He proposed the “Fetal Origins Hypothesis” which claims that impaired foetal health can have long-lasting consequences as it programmes later-life health conditions.
The importance of the womb, however, is difficult to generalise given that many studies use one-time events, like epidemics and famines to establish any causal relationship (see, for example, Almond 2006 and Nelson 2010). Therefore, these studies do not allow drawing any conclusive policy recommendations to address the current child health situation in India. In a recent working paper, we provide new evidence on the origins of child malnutrition (Kumar, Molitor and Vollmer 2014). More precisely, we quantify the effect of drought (periods of rainfall deficiency) experienced in the womb, on the probability of being underweight and/ or anemic, for children under age five. Since the role of weather is especially pronounced for rural population that is dependent on rain-fed agriculture, we focus on rural areas in our analysis, using the second round of the District Level Household Survey (DLHS-2), a national representative dataset. We complement a recent study by Shah and Steinberg (2013) who focus on educational outcomes of children at age six and older by drawing attention to the role of the foetal environment for the health of children under five.
Rainfall variability, maternal and foetal health
Rainfall shocks, specifically periods of droughts, affect maternal and foetal health through (1) income and food prices, and (2) changes in the disease environment. The income effect negatively impacts households due to the high share of the population working directly or indirectly in the agricultural sector, and the high dependency of agriculture on rainfall. The disease environment effect can go in two directions: it can either impose a negative effect on maternal and foetal health due to a reduction in the availability of drinking water, or it can result in a positive effect through a reduction in water-borne diseases.
The overall effect of periods of drought on health is likely to be negative. Even in the presence of positive disease effects, there exists evidence pointing out that the income effect on health dominates the disease effects (Jacoby et al. 2013).
To study the effects of experiencing drought in the womb, we measure rainfall in each child´s district of birth, first, for the year of birth and, second, for the year before birth. Our classification of drought relies on the definition of the Indian Meteorological Department (2010) - a drought year is a year in which district monsoon rainfall falls below 75% of its historical average. Since we focus on deviations from the usual rainfall in a geographical area, less rain-fed districts are not classified as having a higher propensity to drought. In this sense, we argue that our rainfall shock is “exogenous”, meaning that households are unable to foresee the periods of drought and that the shock is common to the whole district population.
Assessing the impact of drought on child health
We estimate the impact of drought experienced in the womb on children’s weight and prevalence of anemia, controlling for the child’s gender, age, caste, parental education, religion, poverty, birth order and quarter of birth. We find that exposure to drought before birth increases the child’s probability of being underweight and severely underweight by 1.7 and 2.1 percentage points respectively. Yet, the association of drought with anemia is not statistically significant. Moreover, we show that a drought in the first year of life is equally important. Children that experience drought after birth are more likely to suffer from moderate and severe undernutrition than children who did not.
We estimate a slightly higher effect of drought for low-caste children compared to high-caste children, and for boys compared to girls (this is consistent with findings in the medical and biological literature that boys are more vulnerable in the womb). However, none of these differences are statistically significant.
We rule out that our results are driven by a general diversity across districts, through differences in adopted health policies, agricultural, and economic conditions that may also be related to child health. Moreover, we show that our main findings are not subject to the way we define drought. Likewise, droughts two or three years before birth are unrelated to the prevalence of underweight, meaning that any foetal effect should only be found for rainfall shocks in the year before birth or, put another way, for shocks that actually occurred during the foetal period.
Weather shocks account for one of the many risk factors for child malnutrition in India. Having established the strong long-lasting role of early life shocks on child malnutrition is an important starting point for policies that target child health. Any effort towards improving child health needs to start at the beginning of human life, namely in the womb.
- As defined by the World Health Organization (WHO), moderate and severe malnutrition (also referred to as undernutrition) is defined as having a weight-for-age z-score below -2 and -3, respectively. Weight-for-age is a standardised measure that compares a child´s weight with that of healthy children of the same age, living under conditions likely to favour achievement of their full genetic growth potential. In other words, weight-for-age captures how much a child´s weight deviates from an international standard of healthy children at the same age.
- Almond, D (2006), “Is the 1918 Influenza Pandemic Over? Long-Term Effects of In Utero Influenza Exposure in the Post-1940 US Population”, Journal of Political Economy, 114 (4), p. 672-712.
- Barker, D (1990), “The Fetal and Infant Origins of Adult Disease”, British Medical Journal, 301 (6761), p. 1111.
- Barker, D (1995), “The Fetal Origins of Coronary Heart Disease”, British Medical Journal, 311 (6998): p.171-174.
- Indian Meteorological Department (2010), ‘Climate Profile of India’, Government of India, New Delhi, India.
- Jacoby, H, S Tiwari and E Skoufias (2013), ‘Monsoon Babies: Rainfall Shocks and Child Nutrition in Nepal’, World Bank Policy Research, Working Paper No. 6395.
- Kumar, S, R Molitor and S Vollmer (2014), ‘Children of Drought: Rainfall Shocks and Early Child Health in Rural India’, Program of the Global Demography of Aging at Harvard University (PGDA), Working Paper No. 116.
- Naandi Foundation (2011), ‘HUNGaMA - Fighting Hunger and Malnutrition’.
- Shah, M and B Steinberg (2013), ‘Drought of Opportunities: Contemporaneous and Long Term Impacts of Rainfall Shocks on Human Capital’, NBER Working Paper Series 19140.
- Nelson, R (2010), “Testing the Fetal Origins Hypothesis in a Developing Country: Evidence from the 1918 Influenza Pandemic”, Health Economics, 19, p. 1181-1192.