The study by researchers at Princeton University's Woodrow Wilson School of Public and International Affairs also found that on average women in both India and sub-Saharan Africa gain only 7 kg throughout pregnancy - just half of the recommended amount.
"These findings should be a wake-up call about maternal nutrition in India," said lead author Diane Coffey, a PhD student at the Wilson School's Office of Population Research.
In 2012, Coffey - who is a co-founder of the research institute for compassionate economics (r.I.C.E.), a non-profit in India - conducted a qualitative study about the health mothers and infants in three Indian villages.
She noticed a pattern: mothers were not gaining weight at the expected rates.
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Body mass and weight gain during pregnancy are important indicators of maternal health. Babies born to undernourished mothers are more likely to be underweight, a characteristic influencing height, cognition and productivity across a lifetime.
As a result, prior studies of maternal health in India have severely missed the mark when calculating pre-pregnancy body weight, researchers said.
The most recent maternal health data was collected in 2005 by the Demographic and Health Survey, which showed that 35.5 per cent of women aged 15 to 49 are underweight.
While this figure is commonly cited, it is actually inaccurate, Coffey said, as women who become pregnant are different from those who do not with regards to body mass.
Using reweighting techniques to correct body mass index scores (BMI), she found that the average BMI of pre-pregnant women in India is 19.5 per cent and the fraction of women who begin pregnancy underweight is 42.2 per cent.
This is almost 7 percentage points higher than the fraction of underweight women between ages 15 and 49.