Low birth weight from 4 states makes up half of India's cases: Study

New Delhi: Cases of a low weight at birth from four states -- Uttar Pradesh, Bihar, Maharashtra, and West Bengal -- account for nearly half of India's cases, despite an overall progress in lowering rates over the last 30 years, an analysis of the National Family Health Survey shows.

The findings are published in the British Medical Journal (BMJ) Global Health.

Having a low birth weight -- under 2.5 kg -- can often signal a mother's underlying health issues and poor nutrition, and has been linked with problems in the child's cognitive development and a vulnerability to chronic conditions in later life.

Analysing data gathered from all five waves of the national survey, researchers from Duke and Harvard universities in the US and institutes in South Korea found that overall, the prevalence of low birth weight in India fell by eight percentage points -- from 26 in 1993 to 18 in 2021.

State-wise, the average prevalence was seen to decline across the five waves of the survey from 25 per cent in 1993 and 1999 to 20 per cent in 2006, and 16 per cent in 2021, when the last wave concluded.

Analysis of data from the fifth wave (2019-21) suggests that 42 lakh babies were born with a low weight in a single year, almost half (47 per cent) of which came from only four states -- Uttar Pradesh, Bihar, Maharashtra and West Bengal.

Prevalence in 1993 was found to be the highest in Rajasthan (48 per cent), while in 2021, Punjab and Delhi saw the highest prevalence at 22 per cent. States such as Mizoram and Nagaland had the lowest prevalence of low birth weight in 1993 and in 2021 as well.

The authors wrote, "The overall prevalence of low birth weight in India declined from 26 per cent to 18 per cent during the period. The 2019-21 survey revealed that four states, Uttar Pradesh, Bihar, Maharashtra, and West Bengal, accounted for almost half of all low-birth-weight births in India." The data from the fifth wave also showed that babies having both a lower weight and a smaller-than-average size at birth were "considerably more likely" to be born to women with little or no formal education and from the poorest households.

"Low birth weight is likely to be more prevalent among non-weighed children since weighing correlates strongly with healthcare infrastructure and being born in a health facility. Also, (a) low socioeconomic status is linked to both lack of access to healthcare and low birth weight," the team wrote.

The results "point to a general decline in the prevalence of low birth weight and convergence between states over time," they said.

The team also highlighted the need for continued efforts in addressing maternal and neonatal health disparities and called for improved data collection at healthcare facilities, which can provide quality data for decision-making across India.

Recorded births were found to increase from 48,959 in 1993 to 2,32,920 in 2021.

Proportion of babies weighed at birth increased over time, resulting in 7,992 being included in the analysis in 1993 (16 per cent) to 209,266 in 2021 (90 per cent), the authors said.