Adequate spacing between births can help to alleviate the likelihood of stunting in children, according to a new study from the Tata-Cornell Institute for Agriculture and Nutrition (TCI).

In an article published in the Proceedings of the National Academy of Sciences of the United States of America, TCI postdoctoral associate Sunaina Dhingra and Director Prabhu Pingali find that differences in height between firstborn and later-born children may be due to inadequate time between births. When children are born at least three years after their older siblings, the height gap between them disappears.

India’s family planning policies have focused on lowering population growth and postponing pregnancy to improve maternal health outcomes. But while the overall fertility rate has fallen as low as 2.1, there has been little progress increasing the period between births. In 2015, approximately 60% of women surveyed waited less than the recommended period of three years between children.

The TCI study shows that placing a greater focus on sufficient birth spacing in maternal and child nutritional policies and public health programs could help to prevent stunting.

“Our research suggests that adequately spacing out births can significantly lower stunting and the myriad bad effects it causes,” Dhingra said. “Policymakers should ensure that family planning programs emphasize the importance of allowing sufficient time between pregnancies, in addition to reducing the number of births and delaying first pregnancies.”

Birth order affects height when births occur less than three years apart, with the height gap increasing between later-born children. However, when the time between births is three years or more, the height advantage of earlier-born children is insignificant.

A marker of chronic undernutrition, stunting is widespread in low- and middle-income countries, with significant, long-lasting implications for children’s wellbeing. Beyond low height, stunting leaves children vulnerable to disease and at risk of lower cognitive ability.

Among the known causes of stunting are poverty, inadequate nutrition, poor diet, poor maternal health during pregnancy and breastfeeding, teen pregnancy, poor disease environment, and frequent illness. Considerable evidence also shows that birth order influences stunting, with children born after the first child at higher risk.

Using data from the fourth round of the Indian Demographic and Health Survey conducted in 2014-15, Dhingra and Pingali confirm that birth order affects height when births occur less than three years apart, with the height gap increasing between later-born children. However, when the time between births is three years or more, they find that the height advantage of earlier-born children is insignificant.

The amount of time between pregnancies affects maternal and child health in several ways. A mothers’ body needs time after birth to replenish key micronutrients, so getting pregnant again too quickly may reduce the nutrients available to the fetus and limit milk production. Having children too close together also makes it more difficult for parents to devote adequate time and resources to each child.

Because of the ubiquity of stunting in developing countries and the serious nature of its social and economic costs, dedicated efforts have been made to curb stunting around the world. As a result, stunting has decreased by 35% since 1990.

Yet, as recently as 2020, 141 million children under the age of five were reported as stunted, and global reductions mask regional disparities. Over 69 million stunted children live in South Asia, with most in India. Understanding the regional and local drivers of stunting can help reduce its incidence in such burdened countries.