Increasing women's access to household environments free from air pollution during pregnancy
Authors: Lorretta Favour Chizomam Ntoimo
Journal: The Lancet Global Health (2024)

Fetal growth restriction can have serious consequences for a baby's health and development, both during pregnancy and throughout their life. As a result, it is important to ensure maternal environments during pregnancy are supportive of fetal growth. In The Lancet Global Health, William Checkley and colleagues1Checkley W Thompson LM Hossen S et al.Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.Lancet Glob Health. 2024; 12: e815-e825Google Scholar report the findings of the Household Air Pollution Intervention Network (HAPIN) trial, a randomised controlled trial conducted in ten resource-poor settings in Guatemala, India, Peru, and Rwanda that investigated the possible influence of cooking with liquefied petroleum gas (LPG)—relative to biomass—on fetal growth outcomes. The authors examined fetal growth data obtained from ultrasound assessments. The primary goal of the study was to assess the possible effects of a multi-component LPG cooking intervention to reduce household air pollution on fetal growth during pregnancy. By thoroughly evaluating the data and using a variety of standardised measuring and analytical tools and procedures, the authors found no benefit of cooking with LPG stoves relative to biomass on fetal growth. Although there is a substantial amount of literature available on this topic, the precise effect of using LPG for cooking purposes during prenatal development remains unknown. Exposure to kitchen fuel smoke, especially LPG, has been associated with reduced fetal growth and birthweight.2Kadam YR Mimansa A Chavan PV Gore AD Effect of prenatal exposure to kitchen fuel on birth weight.Indian J Community Med. 2013; 38: 212-216Crossref Scopus (12) Google Scholar, 3Clasen TF Chang HH Thompson LM et al.Liquefied petroleum gas or biomass for cooking and effects on birth weight.N Engl J Med. 2022; 387: 1735-1746Crossref PubMed Scopus (17) Google Scholar, 4Epstein M Bates MN Arora NK Balakrishnan K Jack DW Smith KR Household fuels, low birth weight, and neonatal death in India: the separate impacts of biomass, kerosene, and coal.Int J Hyg Environ Health. 2013; 216: 523-532Crossref PubMed Scopus (132) Google Scholar Other research, however, has shown no significant association. For instance, Jack and colleagues5Jack DW Ayuurebobi K Gould CF et al.A cluster randomised trial of cookstove interventions to improve infant health in Ghana.BMJ Glob Health. 2021; 6e005599 Crossref Scopus (24) Google Scholar found that substituting biomass cooking stoves with LPG stoves had no significant impact on birthweight in pregnant women. It is worth noting that most previous research on the potential effects of cooking with LPG on fetal growth has been observational and prospective, done in a single location and with a small sample size. Checkley and colleagues1Checkley W Thompson LM Hossen S et al.Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.Lancet Glob Health. 2024; 12: e815-e825Google Scholar expand on the available literature by showing no significant effect of cooking with an unventilated LPG stove compared with biomass on fetal growth and developmental outcomes.1Checkley W Thompson LM Hossen S et al.Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.Lancet Glob Health. 2024; 12: e815-e825Google Scholar The trial also found no association between fetal growth outcomes and personal exposures to particular types of household air pollution. The key strength of this study lies in its design—a randomised control trial conducted in multiple settings and with a large sample size. Despite the strength of the evidence provided by Checkley and colleagues1Checkley W Thompson LM Hossen S et al.Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.Lancet Glob Health. 2024; 12: e815-e825Google Scholar relative to observational and prospective studies, there are some concerns about their findings. Nitrogen dioxide (NO2) is emitted by LPG as well as biomass stoves, which the authors acknowledged as one of the limitations of their trial; further investigation is required to take into account this limitation and other limitations of the trial. According to a systematic review and meta-analysis, maternal exposure to increased NO2 and fine particulate matter (PM2·5) during pregnancy might impede infant head circumference and length growth.6Fu L Chen Y Yang X et al.The associations of air pollution exposure during pregnancy with fetal growth and anthropometric measurements at birth: a systematic review and meta-analysis.Environ Sci Pollut Res Int. 2019; 26: 20137-20147Crossref Scopus (23) Google Scholar According to studies conducted in Scotland and Korea, exposure to air pollution, particularly PM and NO2, has been linked to reduced fetal growth, including smaller head circumference and biparietal diameter.7Clemens T Turner S Dibben C Maternal exposure to ambient air pollution and fetal growth in North-East Scotland: a population-based study using routine ultrasound scans.Environ Int. 2017; 107: 216-226Crossref PubMed Scopus (59) Google Scholar, 8Lamichhane DK Ryu J Leem J-H et al.Air pollution exposure during pregnancy and ultrasound and birth measures of fetal growth: a prospective cohort study in Korea.Sci Total Environ. 2018; 619–20: 834-841Crossref Scopus (36) Google Scholar A prospective cohort study conducted in China also found that indoor air pollution and ambient particulate matter have a deleterious influence on prenatal growth, with higher levels of PM1 and PM2·5 being associated with slower fetal growth.9Zhou S Guo Y Su T et al.Individual and joint effect of indoor air pollution index and ambient particulate matter on fetal growth: a prospective cohort study.Int J Epidemiol. 2023; 52: 690-702Crossref Scopus (2) Google Scholar This implies that household air pollution can have a negative impact on embryonic development and calls for additional research into the effects of complete removal of polluting stoves from the indoor environment on fetal growth outcomes. Furthermore, the analysis by Checkley and colleagues1Checkley W Thompson LM Hossen S et al.Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.Lancet Glob Health. 2024; 12: e815-e825Google Scholar did not account for exposure to biomass stoves before pregnancy or in the early gestational weeks before recruitment, which could have influenced their findings. According to WHO,10WHOHousehold air pollution.https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-healthDate: Dec 15, 2023Date accessed: February 21, 2024Google Scholar 6·7 million premature deaths are caused yearly by ambient and household air pollution. Exposure to household air pollution is also associated with non-communicable diseases that are among the top causes of death globally, such as stroke, ischaemic heart disease, chronic obstructive pulmonary disease, and lung cancer. Most of these deaths occur in low-resource settings. So-called clean fuels and technologies, such as solar energy, electricity, LPG, natural gas, and alcohol fuels, can help to minimise pollution and protect human health. Using the gold standard of experimental design, a randomised controlled trial, Checkley and colleagues1Checkley W Thompson LM Hossen S et al.Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.Lancet Glob Health. 2024; 12: e815-e825Google Scholar showed no protective effect of LPG on fetal development in multiple resource-poor contexts selected from countries at various stages of human development in Asia, southern America, and Africa. In all, their findings emphasise the need for more research into the safety of alternative fuels for fetal development. To accelerate progress towards attaining the UN Sustainable Development Goals pertaining to child health outcomes in low-income and middle-income countries, it is imperative that governments and development organisations promote evidence-based polices and initiatives aimed at increasing women's access to household environments that are free from air pollution during pregnancy. I declare no competing interests. Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trialAlthough an LPG cooking intervention successfully reduced personal exposure to air pollution during pregnancy, it did not affect fetal size. Our findings do not support the use of unvented liquefied petroleum gas stoves as a strategy to increase fetal growth in settings were biomass fuels are used predominantly for cooking. Full-Text PDF Open Access