1 Introduction

Welcome to Reproductive Health in a Warming World, an interdisciplinary and interactive coursebook exploring the profound impact of environmental heat stress on human reproduction—particularly menstruation, fertility, pregnancy, and developmental health.

As climate change accelerates, rising temperatures are becoming one of the greatest threats to human health. This booklet aims to equip learners with an understanding of how the human body responds to heat, how reproductive systems are particularly vulnerable, and what we can do about it.

What You’ll Learn

By the end of this booklet, you will be able to:

• Define heat stress and its physiology

• Explain the body’s thermoregulatory mechanisms

• Describe how sex hormones modulate temperature regulation

• Analyse how heat exposure affects fertility, pregnancy, and fetal development

• Identify molecular and physiological pathways affected by heat

• Explore the interaction between endocrine, immune, and vascular systems under thermal stress

• Reflect on global health equity and climate vulnerability

Who This Book Is For

This booklet was originally designed for onboarding students joining research projects with Sophie in the Environmental Health Equity Lab. However, it may also be helpful for:

• Climate and health policy scholars

• Curious learners interested in the intersection of climate science, biology, and reproductive justice

No specialised background is required—just a willingness to learn about a topic that is becoming increasingly important in a changing world.

Why It Matters

Climate change isn’t just melting ice caps – it’s shaping bodies, families, and futures. Heat stress is now linked to infertility, miscarriage, poor birth outcomes, and metabolic disease. Understanding these pathways is key to advancing reproductive health equity in the 21st century.