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

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. What are the acute and chronic effects of environmental heat exposure on pregnancy and birth outcomes across different trimesters? 2. Through which biological pathways does heat stress impact maternal, fetal, and infant health across varying gestational ages? 3. How do socio-demographic factors, maternal characteristics, and nutritional status of women modify the relationship between environmental heat exposure and adverse pregnancy outcomes? The study will take place in rural parts of Sindh, Pakistan. These areas often experience extreme heat and have limited access to electricity or cooling systems like fans or air conditioners. This study will include pregnant women who are in their first trimester (under 14 weeks of pregnancy). Before starting any study activities, researchers will explain the study to each woman in a language she understands and ask for her written permission to take part (informed consent). At the beginning of the study, participants will visit a study clinic. During this visit, researchers will check their height and weight, perform an ultrasound, and collect a small amount of blood for testing. Participants will also be asked to wear a small device that measures the air temperature and humidity in their surroundings. The researchers will follow each participant during her pregnancy, with visits during the second and third trimesters at the study clinic. At each visit, researchers will check how much heat the participant has been exposed to using the data from the device and from her own answers to a simple questionnaire. The quest