Climate change has led to extreme heat events, disproportionately affecting vulnerable populations. Heat stress during pregnancy is linked to adverse health outcomes, yet the biological mechanisms remain poorly understood. This research study aims to investigate the effect of environmental heat on maternal, fetal and infant health and examine the biological pathways linking heat stress to adverse pregnancy outcomes.

This prospective cohort study will recruit 6000 pregnant women from three districts in Sindh, Pakistan. Eligible participants ≥18 years old, will have a minimum of five scheduled visits from

The study has received ethical approval from the Aga Khan University (AKU) (Ref: 26249) and the Pakistan National Bioethics Committee (Ref: 1065/23/1736). Written informed consent will be obtained from all participants before enrolment. Referral pathways to healthcare facilities will be established to ensure timely management of pregnancy complications. Findings will be disseminated through peer-reviewed publications, scientific conferences, and engagement with policymakers and public health stakeholders to inform climate-resilient maternal health strategies. Results will also be shared with participants and communities through meetings and informal sessions to raise awareness and support evidence-based heat adaptation.

NCT01234567.

Gestational weight gain (GWG) is an important indicator of maternal nutrition to be monitored during pregnancy. However, there is no evidence-based tool that can be used to monitor it across all geographic locations and pre-pregnancy body mass index (BMI) categories. The WHO is undertaking a project to develop GWG charts by pre-pregnancy BMI category, and to identify GWG ranges associated with the lowest risks of adverse maternal and infant outcomes. This protocol describes all the steps that will be used to accomplish the development of these GWG charts.

This project will involve the analysis of individual participant data (researcher-collected or administrative). To identify eligible datasets with GWG data, a literature review will be conducted and a global call for data will be launched by the WHO. Eligible individual datasets obtained from multiple sources will be harmonised into a pooled database. The database will undergo steps of cleaning, data quality assessment and application of individual-level inclusion criteria. Heterogeneity of maternal weight and GWG will be assessed to verify the possibility of combining datasets from multiple sources and regions into a single database. Generalized Additive Models for Location, Scale and Shape will be applied for the construction of the centile curves. Diagnostic measures, internal and external validation procedures will also be performed.

This project will include an analysis of existing study de-identified data. To be included in the pooled database, each included study should have received ethics approvals from relevant committees. Manuscripts will be submitted to open-access journals and a WHO document will be published, including the GWG charts and cut-offs for application in antenatal care.