Slow and Deep Breathing to Lower Blood Pressure in Women With Pregnancy-induced Hypertension

Inclusion Criteria: * Diagnosed with pregnancy-induced hypertension (PIH). Defined as "new hypertension presenting after 20 weeks of pregnancy without significant proteinuria (urinary protein:creatinine ratio greater than 30mg/mmol" by NICE guidelines (2010) OR diagnosed as having one-off high blood pressure but at risk of developing PIH; * Single pregnancy; * Capable of giving informed consent; * Age over 18. Exclusion Criteria: * Under 18 years old; * Referred immediately to obstetric-care after PIH diagnosis for an immediate intervention, with systolic blood pressure over 160 mmHg or diastolic blood pressure over 100 mmHg; * Multiple pregnancy (twins, triplets, etc.); * Current smoker; * Current diagnosis of respiratory diseases; asthma, COPD (Chronic Obstructive Pulmonary disease), bronchitis. (A previous occurrence or diagnosis that has not been present for longer than 1 year ago does not exclude participants, i.e. childhood asthma); * Allergy/reaction to gel used on ECG tabs; * Vulnerable participants who are unable to give informed consent.