Poor maternal mental health in pregnancy and postnatally has an obvious negative impact on the mother but may also adversely affect the child and the wider family. The treatment of severe mental illness during this period can be complicated by several factors: the potential for adverse effects of medication on the foetus or breastfed infant; the reduced acceptability of even low levels of risk; the reduced tolerability of adverse effects for women at this critical and demanding time in their lives; the potential for deterioration into extremely severe and high risk illness, particularly postnatally and its rapidity; and the urgency required for achieving recovery to reduce the risk of long term consequences for both mother and child. Electroconvulsive therapy (ECT), as an alternative or adjunctive treatment for severe perinatal mental illness, may offer some patients fewer such disadvantages than medication or psychological therapies, alone or in combination. The indications for ECT in the perinatal period are the same as those in a non-perinatal population. It has been suggested ECT is not considered often enough in the perinatal period (Focht & Kellner 2012). NICE guidelines state ECT should be considered for pregnant women with severe depression, severe mixed affective states or mania, or catatonia, whose physical health or that of the foetus is at serious risk (NICE 2015). There are no prospective randomised control trials assessing the risk and benefit of ECT in the perinatal population but retrospective data have been collected that can help us evaluate whether ECT is both an effective and safe treatment option.