• A recent study of over 2 lakh births in India found that each additional consecutive day of extreme heat during pregnancy raises the odds of low birth weight by about 1 per cent.
• The trimester matters — first-trimester heat is linked to pre-term birth, second-trimester heat to lower birth weight, and third-trimester heat to higher stillbirth risk.
• Mothers with a low body mass index and women in mountainous, less heat-acclimatised regions face the highest risk.
• Traditional Indian foods rich in cooling, hydrating, and nutrient-dense qualities can help mothers build resilience against heat stress.

Yes, extreme heat during pregnancy meaningfully raises the risk of low birth weight, pre-term birth, and stillbirth, according to a large Indian study — and the risk depends on which trimester the heat exposure occurs in. The good news is that everyday food choices, hydration habits, and rest can help vulnerable mothers cope better with rising temperatures.

How does heat during pregnancy affect a baby's birth weight?

Researchers who studied 2,09,266 births across India between 2015 and 2020 found that heat exposure in the second trimester was most strongly associated with lower birth weight, and that each extra consecutive sweltering day nudged up the odds of low birth weight by roughly 1 per cent after accounting for other factors. The study, led by researchers from the University of Queensland and IIT-Delhi, matched each birth record to local heat conditions across the mother's pregnancy.

This matters because low birth weight is linked to a higher chance of health complications for babies later in life. For expecting mothers, this is a reminder that sustained heat isn't just uncomfortable — it is a physiological stressor that the body has to actively manage, trimester after trimester.

Which trimester is riskiest for heat exposure?

Each trimester carries a different risk: heat in the first trimester raises the odds of pre-term birth, heat in the second trimester is tied to lower birth weight, and third-trimester heat shows the strongest link to stillbirth, though researchers note this last estimate is less certain. In practical terms, this means mothers need heat-protective habits throughout pregnancy, not just during the hottest months.

Staying indoors during peak afternoon heat, keeping the body cool with light cotton clothing, and prioritising fluid-rich meals become especially important as pregnancy progresses.

Why are underweight mothers more vulnerable to heat stress?

Mothers with a low body mass index, below 18.5, face a notably higher risk of low birth weight from heat exposure compared to mothers of a normal weight, the study found. This points to a nutritional gap that starts well before pregnancy — undernourished bodies simply have fewer reserves to buffer against environmental stress.

This is where consistent, nourishing eating matters most. Foods like panjeeri, dry fruit ladoos, and multigrain mixes have traditionally been used across India to help women build strength and energy reserves before and during pregnancy. A daily serving of something like Sampoorna Panjeeri, made with ghee, nuts, and whole grains, can offer the kind of dense, sustained nourishment that supports a mother's body through demanding seasons.

Why do women in mountainous regions face higher heat risk?

The study found that women living in mountainous climate zones were the most affected by prolonged heat extremes, likely because their bodies are less acclimatised to sustained high temperatures compared to populations in traditionally hotter regions. This is an important insight for public health planning, but it also reminds us that heat resilience is partly built over time through diet, hydration, and lifestyle — not something the body develops overnight.

Regions with cooler baseline climates may need to pay closer attention to hydration and electrolyte balance during unexpected heatwaves, since the body hasn't had the same practice regulating itself in extreme heat.

What can pregnant women eat to reduce heat-related risk?

While no food can fully offset extreme heat exposure, traditional Indian eating wisdom offers real, practical tools: hydrating fruits, buttermilk, soaked nuts, and small frequent meals that don't burden digestion in hot weather. Iron and protein-rich foods also help offset the added physiological demands of pregnancy.

• Soaked almonds, dates, and seeds for slow-release energy
• Buttermilk and coconut water to maintain electrolyte balance
• Nutrient-dense snacks like Dry Fruit Ladoo for a quick, wholesome energy boost between meals
• Iron-rich options such as ragi-based foods to support healthy birth weight

Co-author Sagnik Dey of IIT-Delhi noted that the mothers most exposed to extreme heat are often those with the fewest resources to cope with it — the poorest, the least educated, the under-nourished. This underscores why accessible, everyday nutrition, not just clinical intervention, has to be part of the solution.

If you or someone you love is navigating a pregnancy through India's increasingly long, hot summers, small daily habits matter. Try adding iHTF Sampoorna Panjeeri to your routine — a traditional blend designed to nourish and strengthen, one wholesome spoonful at a time.

We're India Heals Through Food — sharing fresh, science-backed nutrition insights like this one every day. Follow us on Instagram and Facebook to stay updated.

Frequently Asked Questions

1. What did the study find about extreme heat and newborn health in India?

The study found that sustained spells of extreme heat during pregnancy are linked to a measurable rise in risk of low birth weight, pre-term birth, and stillbirth. Notably, each additional consecutive sweltering day increases the odds of low birth weight by about 1 per cent after accounting for other factors.

2. How was this study conducted?

Researchers used India's National Family Health Survey (NFHS) data, examining 2,09,266 births recorded between 2015 and 2020. They matched each birth record to local heat conditions experienced by the mother throughout her pregnancy to determine associations with adverse outcomes.

3. Does the timing of heat exposure during pregnancy matter?

Yes, the effect depends on pregnancy stage. First-trimester extreme heat exposure is linked to higher pre-term birth risk, second-trimester heat is associated with lower birth weight, and third-trimester exposure appears linked to the highest stillbirth risk, though this estimate is less certain.

4. Which women face the greatest risk from extreme heat during pregnancy?

Mothers with low body mass index (below 18.5) face notably higher low birth weight risk from heat exposure. Women in mountainous regions are most affected, likely due to lower acclimatisation. Poorest, least educated, and under-nourished mothers also face disproportionate exposure and risk, per the study.

5. What do the researchers recommend based on these findings?

Lead author Vineetha Vincent stressed that protecting pregnant women must be part of India's climate adaptation planning as heatwaves lengthen. Co-author Sagnik Dey emphasized that adaptation responses ignoring the social gradient of vulnerability will fail to protect the women who need protection most.