Entonox, or gas and air, is widely used for pain relief during labour, but the nitrous oxide it contains is a potent greenhouse gas. J O Atkinson/ShutterstockThe NHS has a substantial carbon footprint. Yet one part of its environmental impact receives relatively little attention: maternity care.The health service is responsible for an estimated 4% to 5% of England’s greenhouse gas emissions. A 2025 report from the Royal College of Obstetricians and Gynaecologists estimated that selected maternity care activities in England generated about 205,000 tonnes of carbon dioxide equivalent (CO₂e) in 2022–23.CO₂e expresses the warming effect of different greenhouse gases, such as methane, as an equivalent amount of carbon dioxide. The analysis excluded some maternity services, so the total footprint is likely to be higher.Nearly 29% of the emissions across the activities studied came from Entonox, commonly known as gas and air. It contains nitrous oxide, a potent greenhouse gas. Using it during regular contractions over four hours has an estimated warming effect of 237kg CO₂e.Travel to appointments also contributes to emissions. An analysis at the Whittington, a hospital in north London, estimated that a patient’s return journey to an antenatal appointment generated an average of 1.23kg CO₂e.Hospitals also use large quantities of disposable equipment. Ready-to-use formula bottles and teats, single-use cups and clinical waste containers are routinely used once and discarded.Pregnancy is sometimes described as a “teachable moment”, when people may be particularly receptive to health information. Environmental advice could become part of those conversations, including discussions about feeding a baby or choosing pain relief.Responsibility for reducing emissionsBut placing responsibility on parents creates ethical problems. Maternity care in the UK is already under intense pressure. The 2022 Ockenden review documented serious failures in maternity safety, while the 2024 birth trauma inquiry highlighted how women’s concerns were dismissed or ignored. Read more: Maternity care needs more than answers: it needs change Against that background, asking someone in labour to weigh the climate effects of pain relief alongside their comfort and safety could create another burden at an already demanding time.Measuring emissions can help hospitals improve how services are designed. But carbon targets should not be used to restrict access to caesarean birth or pain relief. Decisions about care should respect each person’s needs and informed choices.In a small interview study involving 12 people who had used nitrous oxide during labour, most wanted environmental information to be available during pregnancy. However, they were unsure whether knowing its impact would change their choice of pain relief. Participants also considered reducing emissions to be primarily the responsibility of healthcare organisations. Nitrous oxide – commonly known as ‘gas and air’ or Entonox – is a 50/50 mix of nitrous oxide and oxygen used for moderate pain and anxiety relief during labour. caseyjadew/Shutterstock A more useful approach is to change how maternity services are delivered while protecting patient choice.Some NHS maternity services are already doing this. At Norfolk and Norwich University Hospitals, a project introduced virtual ward support and care at home for patients with severe pregnancy sickness. By reducing hospital stays, it cut emissions by an estimated 538kg CO₂e over one month. The team projected an annual saving of around 6,462kg if those reductions continued.Newcastle Hospitals NHS Foundation Trust has introduced technology that captures exhaled gas and air and breaks down the nitrous oxide into nitrogen and oxygen, allowing women to continue using gas and air during labour while reducing its environmental impact.Other changes involve purchasing and waste. Thousands of ready-to-use plastic formula bottles and teats are used in maternity care. A 2019 letter from Irish researchers published in the British Medical Journal highlighted waste from unconsumed formula and discarded packaging. Reducing this could lower emissions without restricting access to formula for those who need or choose it.Similar questions apply to disposable products throughout maternity wards. Clinicians work in systems designed around single-use equipment and established waste procedures. Changing those systems is likely to be more effective than expecting individual clinicians to improvise greener alternatives.At the midwife-led White Horse birth centre in Swindon, staff have replaced plastic containers used to dispose of placentas with alternatives made from 96% paper, reducing plastic use and costs.Breastfeeding illustrates how complicated individual responsibility can become. Compared with exclusive formula feeding, exclusive breastfeeding for six months has been estimated to have a carbon footprint 95kg to 153kg CO₂e lower per baby.But feeding decisions depend on health and personal circumstances, including the support available to parents. A more useful approach would be to provide effective support for anyone who wants to breastfeed, while reducing unnecessary waste and emissions from the way formula is purchased, prepared and supplied by maternity services.Better care, lower emissionsThe Green Maternity Challenge, part of a programme led by the Royal College of Obstetricians and Gynaecologists, brought together nine NHS teams to test ways of reducing emissions while improving maternity care. Several projects involved redesigning services to make treatment easier to access or reduce unnecessary hospital stays.Better care and lower emissions can go together. But treating sustainability only as a fortunate side effect risks overlooking opportunities to design maternity services deliberately around lower-carbon care.Hospitals should examine where their emissions come from and give staff the knowledge and resources to reduce them. Changes to purchasing and waste systems, alongside suitable lower-emission technologies, can help services become greener while protecting safe care and informed choice.Childbirth will always carry an environmental footprint. Health services have the responsibility and practical means to reduce the impact through changes to how care is organised and delivered. Those changes should protect choices without placing additional burdens on the person giving birth.Alice Craggs does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.