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

NCT06957769 | Recruiting

• 2 other identifiers: 2025-8888-34528227190/Z/23/Z
• Study Type: observational
• Target: 6,000
• Locations: 1 country
• Sites: 3

Brief Summary

The goal of this study is to learn how being exposed to high environmental temperatures during pregnancy affects the health of pregnant women and their babies. The study also aims to understand how the body responds to heat stress during pregnancy and how this might lead to pregnancy complications and birth problems like early birth or low birth weight. The main questions that the study aims to answer are:

1. 1.What are the acute and chronic effects of environmental heat exposure on pregnancy and birth outcomes across different trimesters?
2. 2.Through which biological pathways does heat stress impact maternal, fetal, and infant health across varying gestational ages?
3. 3.How do socio-demographic factors, maternal characteristics, and nutritional status of women modify the relationship between environmental heat exposure and adverse pregnancy outcomes?

Conditions

Low Birth Weight Baby; Small for Gestational Age (SGA); Preterm Birth; Pregnancy Complications; Birth Outcome, Adverse; Heat Strain; Infant Morbidity; Infant Mortality; Neonatal Mortality

Keywords

heat stress; high ambient temperature; climate change; birth outcomes; pregnancy; cohort study; Pakistan

Outcome Measures

Primary Outcomes (2)

• Incidence of Low birthweight (LBW)

  Defined as birth weight less than 2,500 grams (5.5 pounds). Newborn weight will be measured within 48 hours of birth using a calibrated Seca 354 infant weighing scale, precise to 0.1 kg. Measurements will be taken independently by two trained anthropometrists. If the difference exceeds 0.05 kg, a third measurement will be taken. Quality assurance procedures and calibration protocols aligned with INTERGROWTH-21st standards will be followed. LBW will be analyzed as a binary outcome (Yes/No) to assess its association with prenatal heat stress exposure across different gestational windows.

  Within 48 hours of birth

• Incidence of Small Vulnerable Newborns (SVN) births

  All live newborns who are either preterm, Small for Gestational Age (SGA), or Low Birth Weight (LBW)

  At the time of delivery

Secondary Outcomes (9)

• Incidence of Miscarriage

  From enrollment till 22 completed weeks of gestation

• Incidence of Pre-term birth

  At the time of delivery

• Incidence of Small for Gestational Age (SGA)

  At the time of delivery

• Incidence of Stillbirth

  From 22 weeks of gestation till birth

• Incidence of Gestational Hypertension

  From 20 weeks of gestation till birth

Study Arms (1)

Pregnancy cohort

Pregnant women, more than 18 years of age and residents of study sites Matiari, Tharparkar and Tando Muhammad Khan

Other: heat stress

Interventions

heat stress OTHER

Heat stress (exposure) will be quantified using validated environmental heat stress indices, including the mean Heat Index (HI). The heat index represents the apparent temperature or how hot it feels to the human body when air temperature is combined with relative humidity. Individual-level ambient temperature heat exposure will be assessed using wearable temperature and humidity loggers.

Pregnancy cohort

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Only individuals who self-identify as women and are currently pregnant are eligible to participate
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Pregnant women residing in peri-urban and rural areas of the three districts of Sindh, i.e., Matiari, Tharparkar and Tando Muhammad Khan

You may qualify if:

• 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

You may not qualify if:

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

Sponsors & Collaborators

• Aga Khan University: lead

Study Sites (3)

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

Biospecimen

Retention: SAMPLES WITH DNA

For the sub-cohort of 1000 women, nasopharyngeal swabs and stool samples will be retained during pregnancy. At delivery. their placental samples will be retained. Breastmilk sampling will be done in first six months after delivery.

MeSH Terms

Conditions

Premature Birth; Pregnancy Complications; Infant Death; Heat Stress Disorders

Interventions

Heat-Shock Response

Condition Hierarchy (Ancestors)

Obstetric Labor, Premature; Obstetric Labor Complications; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Death; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Wounds and Injuries

Intervention Hierarchy (Ancestors)

Stress, Physiological; Physiological Phenomena

Study Officials

• Jai K Das, MBBS, PhD Public Health

  Aga Khan University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jai K Das, MBBS, PhD Public Health

CONTACT

+92 21 34869826; jai.das@aku.edu

Asma A Malik, MBBS, MSc Epi & Biostats

CONTACT

+923311388051; asma.qureshi@aku.edu

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Doctor

Study Record Dates

• First Submitted: May 2, 2025
• First Posted: May 4, 2025
• Study Start: May 7, 2025
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2028
• Last Updated: December 3, 2025

Record last verified: 2025-11

Locations

PA (3)