Asthma is a very common long-term condition that affects a persons airways and breathing. Approximately one adult in 13 is currently being treated for asthma in the UK (NHS, 2006). Asthma is an acute respiratory illness which is characterised by airway obstruction, airway inflammation and increased responsiveness to various stimuli including environmental irritants, viral respiratory infections, cold air and exercise. Asthma has been thought to be linked to an overactive immune system. In an asthma attack, the bronchi are irritable and have a tendancy to become swollen and inflamed, producing excess mucus that can block the smaller airways. (Swiet, 2002). The muscle in the walls of the airways contracts causing narrowing ( see appendix 1). Asthma attacks can vary in severity from mild breathlessness to respiratory failure. The main symptoms are wheezing, breathlessness, dry cough and a tightness in the chest. In a severe attack, breathing becomes increasingly difficult resulting in a low level of oxygen in the blood. Left untreated, such attacks can be fatal (Peters, 2004). Sometimes allergens such as pollen or dust also act as triggers to asthma. This condition can also be exacerbated by emotional stress which is quite common in pregnancy. During pregnancy, there are many changes in the Respiratory system that are controlled by hormonal and mechanical factors. Whilst the vital lung capacity remains the same (the maximum amount of air that can be moved from maximum inspiration to maximum expiration) during pregnancy, the total capacity is reduced due to the diaphragm rising with increasing gestation (Lavery, 1999). There is an increase in oxygen consumption which is associated with increased ventilation of up to 40%. This is achieved by increasing tidal volume from 500 to 700ml rather than an increase in respiratory rate Residual volume, the volume or air in the lungs which remains at the end of expiration (Swiet, 2002).Asthma affects approximately 4% of all women. About a third of women with asthma experience improvement while they are pregnant, about a third get worse, and about a third stay the same. De Swiet, 2002 suggests that despite changes in the respiratory system during pregnancy, it doesn’t seem to have a great effect on asthma , however the effect asthma has on pregnancy is different. Women with uncontrolled asthma are more likely to have complications during pregnancy. Their babies are more likely to be born pre-term, small or underweight at birth and to require longer hospitalisation after the birth. The more severe the asthma, the greater the risk to the fetus. In rare cases, the fetus can die from oxygen deprivation. Schatz (1992) suggests that asthmatic women are more likely to develop hyperemesis gravidarum, chronic hypertension and antepartum haemorrhage although the causes are unknown. Asthma most commonly exacerbates during the 24th to 36th week of gestation, whereas asthma rarely flares during the last 4 weeks of pregnancy and during labour and delivery. Within 3 months after delivery, almost 75% of women return to their pre-pregnancy status (Blaiss, 2004) >