Hypertension in pregnancy is associated with significant maternal-foetal morbidity and mortality. Obstructive sleep apnoea (OSA) occurs as a result of upper airway narrowing and may contribute to hypertension in pregnancy. Treatment with continuous positive airway pressure (CPAP) improves blood pressure control in non-pregnant hypertensive patients with OSA. We will assess the impact of CPAP treatment on blood pressure control and obstetric outcomes in snoring women with hypertension in pregnancy. We will recruit women referred with hypertension in pregnancy before 20 weeks gestation. Those who snore regularly will be randomised to receive CPAP or standard care. All women will continue to be managed through obstetric clinics where they will have their blood pressure managed in a standardised way by medical staff blinded to the use of CPAP. We expect the CPAP treated group to have significantly better control of their blood pressure, requiring fewer medications and having better obstetric outcomes.