©BMJ Publishing Group Ltd 2014. Guidelines encourage the use of self monitoring of blood pressure in pregnancy, and research suggests that women prefer it. But Hodgkinson and colleagues explain that our enthusiasm may run ahead of the evidence and call for more research before it is routinely adopted Self monitoring of blood pressure is increasingly popular with patients and healthcare professionals. Around a third of people with hypertension self monitor,1 and measurements are more accurate than readings taken in clinic.2 Anecdotal reports in the UK suggest that self monitoring in pregnancy is commonplace, although no studies have assessed this. A Canadian pilot survey found that two thirds of women with gestational hypertension were self monitoring.3 Another small Canadian survey found that 78% of obstetricians used self monitoring in preference to ambulatory measurement to check for white coat hypertension in pregnant women with raised blood pressure.4 Blood pressure guidelines recommend home monitoring for pregnant women with chronic hypertension and poorly controlled blood pressure and for women with gestational hypertension-for example, the 2013 American College of Obstetricians and Gynaecologists guidelines5-so it is likely that the practice will become more common. The American Heart Association, American Society of Hypertension, and Preventive Cardiovascular Nurses Association joint statement6 and European Society of Hypertension guidelines have highlighted the importance and potential of self monitoring blood pressure, with the American guidelines describing it as "theoretically ideal for monitoring changes in blood pressure during pregnancy."7 Although home monitoring in pregnancy may have some advantages, there are still many unanswered questions about its use (box 1). We discuss the available evidence on self monitoring and suggest a way forward.