Effects of heat exposure on self-reported heat strain symptoms among pregnant and postpartum women in South Africa
Abstract Heat exposure can harm pregnant and postpartum women, yet heat strain symptoms in this population remain underexplored. This study implemented a novel mobile application and assessed the environmental context of five self-reported heat strain symptoms: skin rashes, sleep disturbances, dizziness, thirst, and exhaustion among pregnant and postpartum women in Tshwane, South Africa. Symptoms were assessed through interviewer-administered questionnaires at three time points over six months ( N = 201). Self-reported heat strain was analysed against maximum Wet Bulb Globe Temperature (WBGTmax) and air temperature (Tmax). An additional symptom, wetness sensation, was collected continuously via self-reporting using the application and related to the Universal Thermal Climate Index (UTCI). Generalised Estimating Equation models and General Linear Mixed Models accounted for repeated measures. Four of five symptoms showed significant associations with both WBGTmax and Tmax. Wetness sensation was significantly correlated with UTCI. Thresholds for heat strain symptoms identified through Receiver Operating Characteristic curves ranged between 18.53 °C and 26.16 °C WBGTmax, reflecting differences in perceived severity. Urine specific gravity showed inconsistent association with heat, likely due to measurement timing limitations. Although risk varied across symptoms and threshold modelling was exploratory, this study highlights the adverse health consequences of heat exposure for pregnant and postpartum women, which may inform future interventions.
Authors
- Günter Alce (ORCID: https://orcid.org/0000-0001-9112-2414)
- Jakob Eggeling (ORCID: https://orcid.org/0000-0003-0613-3704)
- Nasser Fardousi (ORCID: https://orcid.org/0000-0002-0306-8612)
- Michalis Koureas (ORCID: https://orcid.org/0000-0003-0289-6595)
- Mian Bao
- Zeenat Sulaiman
- Federica Nobile (ORCID: https://orcid.org/0000-0002-8040-8975)
- Craig Parker
- Giorgia Gon (ORCID: https://orcid.org/0000-0002-9741-7712)
- Jean Le Roux (ORCID: https://orcid.org/0009-0000-7229-3031)
- Birgit Kerstens (ORCID: https://orcid.org/0000-0001-8016-8871)
- Ijeoma Solarin (ORCID: https://orcid.org/0000-0002-2045-3053)
- Fani Kalala (ORCID: https://orcid.org/0009-0001-5588-8014)
- Nathalie Roos (ORCID: https://orcid.org/0000-0001-9752-2355)
- Jeroen de Bont (ORCID: https://orcid.org/0000-0001-9924-5961)
- Vassiliki Benetou (ORCID: https://orcid.org/0000-0002-0415-0386)
- Shobna Sawry (ORCID: https://orcid.org/0000-0002-3845-4863)
- Olimpia Lamberti (ORCID: https://orcid.org/0009-0004-6650-6124)
- Giulia Greco (ORCID: https://orcid.org/0000-0002-5448-9521)
- Tobias Monthaler
- Jaspar Maguma
- Koen van der Sanden
- Xara Skentou
- Chuansi Gao (ORCID: https://orcid.org/0000-0001-7386-692X)
- Jeffrey Dirawo
- Chara Bogogiannidou
- Concilia Mutasa (ORCID: https://orcid.org/0000-0002-6073-276X)
- Leslie Nyoni
- Jetina Tsvaki
- Rose Refilwe Lamola
- Pascalia Munyewende
- Celeste Madondo
- Elizabeth Dangaiso
- Llyod Pisa
- Progress Chiworeka
- Bongani Mutimutema
- Maria Kyritsi
- Ioannis Messinis
- Christina Messini
- Chloe Brimicombe
- Boris Kingma
- Anayda Portela
- Jo Borghi
- Matthaios Speletas (ORCID: https://orcid.org/0000-0003-1287-7734)
- Sibusiso Mkwananzi (ORCID: https://orcid.org/0000-0002-4384-2641)
- Nicholas Brink (ORCID: https://orcid.org/0000-0002-6843-6236)
- Cherie Part (ORCID: https://orcid.org/0000-0002-3281-1671)
- Susanne Frennert
- Clara Heil (ORCID: https://orcid.org/0009-0008-5466-8010)
- Isabelle L. Lange
- Darshnika Lakhoo
- Aquinius Mung'atia (ORCID: https://orcid.org/0000-0003-2168-9516)
- Rose Lamola
- Isabelle Lange
- Debra Jackson
- Matthew Chersich
- Andreas Flouris
- Barbara Mouchtouri
- Brian Mqondisi Sibanda
- Ilona Otto
- Veronika Tirado
- Katharine Wieser
- Mags Beksinska
- Christos Hadjichristodoulou
- Stanley Luchters
- Ioanna Voulgaridi
- Paul Lokubal
- Tariro Chinozvina
- Veronique Filippi
- George Daskalakis
- Massimo Stafoggia
- Tapiwa Nyakabau
- Androniki Naska
- Vana Papaevagelou
- Fortunate Machingura
- Olof Stephansson
- Thabani Moronzie
- the HIGH Horizons Study Group
- Clara Sofia Heil
- Sohail Baloch
- Gloria Maimela
- Anastasia Tania Konstantinidou
- Lebohang Radebe
- Claudia Hanson
- Perkins Watambwa
- Jørn Toftum
Institutions
- University of Thessaly (GR)
- Netherlands Organisation for Applied Scientific Research (NL)
- University of Graz (AT)
- University of the Witwatersrand (ZA)
- Liverpool School of Tropical Medicine (GB)
- Ghent University Hospital (BE)
- Karolinska Institutet (SE)
- Ghent University (BE)
- London School of Hygiene & Tropical Medicine (GB)
- ASL Roma (IT)
- World Health Organization (CH)
- Aga Khan University Nairobi (KE)
- Design Science (United Kingdom) (GB)
- Centre for Sexual Health and HIV AIDS Research (ZW)
- Azienda Sanitaria Locale Roma 3 (IT)
- Technical University of Munich (DE)
- Technical University of Denmark (DK)
Publication Details
- Journal
- npj Digital Public Health
- Published
- 2026-09-13
- DOI
- https://doi.org/10.1038/s44482-026-00036-4
- Primary Topic
- Thermoregulation and physiological responses
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- London School of Hygiene and Tropical Medicine
- UK Research and Innovation
- European Commission
- Lunds Universitet
- HORIZON EUROPE European Research Council