Short Birth Intervals Linked to Moderate and Severe Child Anemia in India

In India, roughly two out of every three young children carry too little hemoglobin in their blood to transport oxygen efficiently. According to the fifth National Family Health Survey (NFHS-5), conducted in 2019–21, 67.1 percent of children aged six to fifty-nine months are anemic, a burden that makes child anemia one of the country’s most pressing public health and nutrition challenges. A new analysis of NFHS-5 data, published in Frontiers in Nutrition, adds a striking dimension to this picture: how closely a child’s birth follows a previous one may shape not just whether the child becomes anemic, but how severe the condition turns out to be. The study, led by Soumen Barik, Arpita Show, and Manoj Sonune, found that children born after a short birth interval had significantly higher odds of moderate and severe anemia. With 47.8 percent of Indian women experiencing a short birth interval during 2019–21, the finding highlights a potentially modifiable lever in the fight against a condition that impairs cognition, growth, and survival.

The researchers drew on the NFHS-5, a nationally representative household survey implemented by the International Institute for Population Sciences in Mumbai under the Ministry of Health and Family Welfare, with technical support from the Demographic and Health Surveys Program. Using a multistage stratified sampling design, the survey covered 636,699 households, 724,115 women aged fifteen to forty-nine, and 232,920 children aged under five across all Indian states and union territories. Trained interviewers collected data through computer-assisted personal interviewing in eighteen Indian languages, and hemoglobin concentrations were measured with a battery-operated portable HemoCue Hb 201+ analyzer, adjusted for altitude following survey protocols. Following World Health Organization guidelines, children were classified as not anemic (hemoglobin at or above 11.0 grams per deciliter), mildly anemic (10.0–10.9), moderately anemic (7.0–9.9), or severely anemic (below 7.0). A short birth interval was defined, per WHO and DHS conventions, as fewer than thirty-three months between two consecutive live births; intervals of thirty-three months or more served as the comparison group.

Reaching the final analytical sample required extensive exclusions. The researchers began with 232,920 mother–child pairs, removed never-married women since childbearing in India occurs predominantly within marriage, excluded mothers with only one child because birth intervals require at least two live births, dropped children who were not alive at the time of the survey, and removed infants under six months who are not eligible for anemia testing under NFHS-5 protocols. Finally, 50,460 observations with missing data on key variables—most often anemia severity, birth interval, maternal anemia, or maternal body mass index—were excluded without imputation, leaving 101,240 children with complete information. The authors chose a complete-case approach because most missing data occurred in the primary exposure or outcome variables, where imputation risks introducing artificial bias.

The statistical strategy reflected a technical subtlety. Although anemia severity is an ordinal outcome, a Brant test revealed that the proportional-odds assumption was violated for the overall model (chi-square 463.07, p < 0.001) and for the birth-interval predictor itself, meaning predictor effects differ across severity thresholds. The team therefore used survey-weighted multinomial logistic regression, which estimates category-specific associations, incorporating sampling weights, primary sampling units, and strata to account for the complex survey design. Potential multicollinearity among covariates was checked with variance inflation factors, which averaged 1.62 and never exceeded 3.1. The model adjusted for child sex, age, birth weight, and birth order, plus maternal age, education, age at first birth, place of delivery, anemia, body mass index, anganwadi benefits, and mass media exposure, alongside household wealth, size, caste, religion, residence, and geographic region.

The headline result was a graded association. Compared with children born after a non-short interval, those born after a short interval had 10 percent higher odds of moderate anemia (adjusted odds ratio 1.10; 95 percent confidence interval 1.05–1.15) and 18 percent higher odds of severe anemia (1.18; 1.05–1.34), while the association with mild anemia was not statistically significant. Descriptive figures pointed the same way: 29.9 percent of children in the short-interval group were not anemic, compared with 32.2 percent in the comparison group, while moderate anemia affected 39.2 percent versus 36.5 percent and severe anemia 2.3 percent versus 2.1 percent. The pattern suggests that closely spaced births push children deeper into the anemia spectrum rather than simply tipping them over the mild threshold.

Why might short birth intervals deepen anemia? The leading explanation is the maternal nutritional depletion hypothesis. Pregnancy and lactation substantially drain maternal stores of iron and other essential micronutrients, including folate, vitamins A and B12, zinc, and calcium. The female reproductive cycle moves through pregnancy, full lactation, partial lactation, and a non-pregnant, non-lactating recovery period; when conception occurs during lactation, these phases overlap and maternal nutrient demands rise sharply. Without adequate dietary and supplemental intake, closely spaced pregnancies leave too little time to replenish depleted reserves, increasing the risk of maternal anemia and poor nutritional status. Depleted maternal nutrition can limit the transfer of iron to the fetus, leaving newborns with critically low iron stores and raising the likelihood of preterm birth and low birth weight, both strongly linked to early-onset anemia. Postnatally, the physiological stress of a pregnancy–lactation overlap may degrade breast milk volume and immunological quality, depriving the nursing infant of bioavailable iron. Behaviorally, concurrent childcare and pregnancy may lead to early weaning and delayed introduction of nutrient-rich complementary foods, while closely spaced births dilute household dietary, healthcare, and financial resources among multiple young children. The authors caution that maternal nutritional depletion was not directly measured in this study, so these forces remain plausible contextual explanations rather than confirmed mechanisms.

The adjusted analysis identified clusters of exceptional vulnerability. Children aged six to twenty-three months bore the heaviest burden, with 49.81 percent moderately and 3.40 percent severely anemic in bivariate comparisons; by 42–59 months, odds of moderate and severe anemia fell dramatically (adjusted odds ratios 0.24 and 0.12 relative to the youngest group), possibly reflecting greater dietary diversity and longer exposure to iron–folic acid supplementation, deworming, and growth monitoring. Low birth weight below 2,500 grams raised the odds of severe anemia by 58 percent (1.58; 1.38–1.82), consistent with lower neonatal iron stores and higher iron demands during catch-up growth. Maternal anemia showed a dose–response pattern: children of severely anemic mothers had more than sevenfold higher odds of severe anemia (7.04; 5.42–9.14). Maternal underweight was also associated with moderate (1.13) and severe (1.23) anemia, while female children had lower odds of severe anemia than males (0.85).

Structural inequities ran through the findings. Children from Scheduled Caste and Scheduled Tribe communities had higher odds of moderate (1.18; 1.10–1.27) and severe (1.32; 1.10–1.59) anemia than the general category, which the authors link to socioeconomic deprivation, poor living conditions, intergenerational nutritional deficits, and cereal-based diets containing fewer iron-rich foods. Maternal education emerged as strongly protective: children of mothers with higher education had 48 percent lower odds of severe anemia (0.52; 0.40–0.67) than children of unschooled mothers, potentially reflecting better health literacy, dietary diversity, hygiene, and use of preventive services. Greater household wealth lowered the odds of moderate anemia, and any exposure to mass media was associated with lower odds of moderate anemia (0.91), suggesting that information channels themselves may shape nutrition outcomes.

Geography mattered as much as caste or schooling. Compared with the eastern region, children in the west (adjusted odds ratio 2.88), north (2.65), central (1.63), and south (1.77) had substantially higher odds of severe anemia, while the northeast stood out with 59 percent lower odds (0.41). The authors attribute the northern and central burdens to entrenched patriarchal norms, limited dietary diversity, cereal-based diets, poor sanitation, and infectious disease burdens, with endemic malaria and hemoglobinopathies possibly contributing in central India. The northeast’s advantage may reflect greater female autonomy, lower fertility, and diets richer in animal-source foods. These regional and caste disparities, the researchers conclude, point to broader structural and nutritional inequalities that intersect with birth spacing to shape child health.

The study’s strengths include its scale and generalizability, its graded rather than binary treatment of anemia, and comprehensive adjustment for confounders. But the cross-sectional design precludes causal claims: associations between short birth intervals and anemia severity cannot establish that spacing causes anemia, and longitudinal studies are needed to confirm the pathways. The restriction to ever-married women, the inferential status of the nutritional depletion mechanism, and possible selection bias from complete-case analysis further temper interpretation. Nevertheless, the authors argue the findings carry actionable weight. They call for integrated strategies that promote optimal birth spacing, strengthen family planning services, and deliver targeted maternal nutrition interventions for marginalized populations, alongside improved infant and young child feeding practices. Such measures, they conclude, would support progress toward Sustainable Development Goal 2 on zero hunger and Goal 3 on good health and well-being.

Subject of Research: Childhood anemia and birth spacing in India

Article Title: Association between short birth intervals and childhood anemia severity in India: evidence from the fifth National Family Health Survey (NFHS-5)

Article References: Barik, S., Show, A., & Sonune, M. (2026). Association between short birth intervals and childhood anemia severity in India: evidence from the fifth National Family Health Survey (NFHS-5). Frontiers in Nutrition, 13, Article 1945328. https://doi.org/10.3389/fnut.2026.1945328

Image Credits: AI Generated

DOI: 10.3389/fnut.2026.1945328

Keywords: childhood anemia, India, NFHS-5, short birth interval, maternal nutrition, health inequities, Association, between, short, birth, intervals, childhood