The purpose of this study is to learn whether a simple, traditional, and balanced meal made from local foods, eaten once a day during pregnancy, can help women in rural Pakistan stay healthier in hot weather and give birth to healthier babies. Climate change has made heat a serious challenge for pregnant women, especially in areas with limited resources. This study will explore whether an indigenous meal that is culturally acceptable and easy to prepare can improve resilience to heat stress and support better outcomes for both mothers and newborns.

The study will focus on two main questions:

• Can this daily balanced meal reduce the harmful effects of heat stress during pregnancy?
• Does it improve newborn health, especially birth weight?

Researchers will compare women who eat the balanced local meal every day with women who continue their usual meals. They will check changes in women's health, levels of key vitamins and nutrients, and their babies' birth outcomes.

During the study, participants will:

• Either eat the balanced local meal daily or continue their usual meals.
• Share information on their health, diet, and heat exposure.
• Provide small samples, such as blood and stool, to study nutrient levels and gut health.
• Have their newborns' health and growth measured at birth.

This study will use a quasi-experimental design to study if the effects of an indigenous heat-mitigating balanced dietary intervention on maternal health and neonatal development when implemented from preconception to delivery in a region with high temperatures.

The study will recruit 292 women of reproductive age who plan to become pregnant and assign them to either the intervention group or the comparison group in a 1:1 ratio. The intervention group will receive one customized indigenous heat-mitigating balanced diet as daily lunch meal (~1,000 kilocalories). The comparison group will continue their usual dietary practices while receive routine antenatal care and dietary counseling services according to national guidelines.

The intervention diet plans have been designed through review of dietary recommendations and published evidence, combined with community consultations to ensure feasibility and cultural acceptability. The food choices were established according to three criteria which required foods to have high nutrient content and be affordable and accessible within the local area. The meal composition includes whole grains, lentils, legumes, green leafy vegetables, dairy products, fermented foods, fish, and other culturally acceptable animal-source foods. A 14-day rotating menu will be implemented. The intervention will begin at least one month prior to conception and continue until delivery.

Meals will be prepared in kitchen in field site's office set up specially for meals preparation. Local chefs will be hired and counselled to prepare meals ensuring proper hygiene and following study's diet plans. Study data collectors will distribute meals to the participants. The team will use attendance records, intervention adherence forms, telephone follow-up and home visits to monitor intervention delivery. The team will organize home delivery services when they become essential.

The research team will evaluate maternal health at the end of each trimester starting from the time of conception until the end of pregnancy. Data will be collected through three different methods which include anthropometer, vitals assessments and testing blood samples for hemoglobin levels using point of care testing device (HemoCue 301+) and specific micronutrients & inflammatory markers (Vitamin A, D, B9, B12, Zinc, Ferritin and CRP). The research team will collect stool samples to investigate gut microbiome composition through molecular techniques. The study will use weather stations, thermal drone cameras and wearable devices (FitBit) to measure heat exposure while linking those measurements to local weather patterns.

At delivery, neonatal anthropometric measurements will be obtained using standardized procedures. Study staff will collect cord blood samples which will then undergo biomarker analysis. Moreover, placental tissues will be collected for both gross examination and transcriptomic analysis.

For safety purposes, all individuals will be monitored carefully for food allergies by conducting regular assessments and establishing health facility connections to treat any medical complications. The study allows participants to join voluntarily while they maintain their right to leave at any moment without losing access to standard medical treatment.

The study has received ethical approval from the Aga Khan University Ethical Review Committee (Reference: 2024-10697-3239) and the National Bioethics Committee of Pakistan (Reference: 4-87/NBCR-1220/24-25/836). Written informed consent will be obtained prior to enrollment. Data will be managed in accordance with institutional confidentiality and data protection policies.

Inclusion Criteria:

1. Women aged 18-45 years belonging to a low to middle socioeconomic status, residing in Mithi, Districts in Sindh.
2. Planning to conceive within the study time frame and expect to become pregnant within four months of starting nutritional intervention.
3. Women who confirm their pregnancy during the first trimester i.e., before 8 weeks of gestational age.

Exclusion Criteria:

1. Women using long-lasting contraceptives such as IUDs, implants, and injectable methods like Depo-Provera.
2. Women with a history of multiple miscarriage or stillbirths.
3. Women with known chronic diseases, such as cardiovascular disorders, hepatic disorders, renal disorders, and infectious diseases.
4. Women suffering from severe malnutrition (WHO: Underweight i.e., having BMI < 16 Kg/m2 or obese having BMI ≥ 30 Kg/m2).
5. Women having severe anemia (WHO: Severe anemia i.e., Hb < 7g/dL).
6. Women currently enrolled in BISP supplementation programs or taking any supplements other than iron and folic acid (IFA) will be excluded from the study.
7. Those who do not become pregnant within three months of supplementation during pre-conception.

women of reproductive age

Individual Participant Data (IPD) will not be made available to anyone including other researchers. Participant confidentiality and privacy protection will be given utmost importance as even anonymized data could have potential indirect identifiers due to the particular locality of the study in a specific rural community, which may lead to the re-identification of participants and may damage the reputation of the community, or stigmatize the participants. Informed consent was also not obtained from the participants regarding sharing of personal data with the public. Thus, we will prioritize our ethical commitment by only making available results of the study in aggregated group format.

single-blind approach (Investigator and Outcomes Assessor Blinding): The investigators and outcome assessors will remain unaware of the group assignments. They will not be involved in the preparation or distribution of the intervention meals to ensure that their observations and assessments remain unbiased. However, participants will not be blinded, as they will be aware of whether they are receiving the indigenous balanced diet or continuing their usual meals.