How higher temperatures affect pregnant women and newborns in rural Sindh

Biological Impacts of Rising Temperatures on Maternal, Fetal, and Newborn Health: A Cohort Study (BIRTH Cohort)

This cohort will test whether exposure to high environmental temperatures during pregnancy increases the chances of early birth, low birth weight, or other complications for pregnant women in rural Sindh.

Quick facts

• Study type: Observational
• Enrollment: 6000 (estimated)
• Ages: 18 Years and up
• Sex: Female
• Sponsor: Aga Khan University (other)
• Drugs / interventions: radiation
• Locations: 3 sites (Matiari, Sindh and 2 other locations)
• Trial ID: NCT06957769 on ClinicalTrials.gov

What this trial studies

This prospective cohort will enroll pregnant women at or before 13 weeks and 6 days of gestation in rural districts of Sindh and follow them through delivery to track maternal and newborn outcomes. Researchers will measure environmental heat exposure using local ambient temperature data and likely personal or community-level heat metrics while collecting clinical data and biospecimens. Primary outcomes include preterm birth, low birth weight, and small-for-gestational-age status, with additional monitoring for pregnancy complications such as hypertensive disorders and gestational diabetes. Analyses will examine acute and chronic heat effects across trimesters and how maternal nutrition and sociodemographic factors modify those relationships.

Who should consider this trial

Good fit: Ideal participants are pregnant women aged 18 or older with a confirmed single or multiple pregnancy at ≤13 weeks and 6 days who are permanent residents of the study district and plan to deliver there while able to attend study visits.

Not a fit: Women who plan to relocate outside the district for more than three months during pregnancy, who cannot attend study visits, or who enroll after the first trimester are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, the findings could identify heat-related risks during pregnancy and inform interventions or policies to protect mothers and newborns in hot, low-resource settings.

How similar studies have performed: Epidemiological studies have linked higher temperatures to greater risks of preterm birth and low birth weight, but cohort data probing biological pathways and results from low-resource settings are still limited, so this approach is partly tested but fills an important gap.

Eligibility criteria

Inclusion Criteria:

* Single or multiple live pregnancy confirmed through ultrasound
* Gestational age less than or equal to 13 weeks and 6 days at enrollment
* At least 18 years of age
* Permanent resident of the study district and plans to deliver within the district
* Willing and able to attend study clinic visits and comply with study procedures throughout pregnancy

Exclusion Criteria:

• Plan to relocate outside the district for more than 3 months during the study period

Where this trial is running

Matiari, Sindh and 2 other locations

• Matiari Research and Training Centre — Matiari, Sindh, Pakistan (RECRUITING)
• Mithi Study Site Office — Mithi, Sindh, Pakistan (RECRUITING)
• Tando Muhammad Khan (TMK) Study Site Office — Tando Muhammad Khan, Sindh, Pakistan (RECRUITING)

Study contacts

• Principal investigator: Jai K Das, MBBS, PhD Public Health — Aga Khan University
• Study coordinator: Jai K Das, MBBS, PhD Public Health

Conditions: Low Birth Weight Baby, Small for Gestational Age, Preterm Birth, Pregnancy Complications, Birth Outcome, Adverse, Heat Strain, Infant Morbidity, Infant Mortality