has different levels of safety for the fetus. Given late in pregnancy, antipsychotic agents and lithium can have adverse effects on the infant. Stopping mood-stabilisers carries a higher risk for bipolar episode recurrence during pregnancy. Home treatment and hospitalization It has been recognized since the 19th century that it is optimal for a woman with puerperal psychosis to be treated at home, where she can maintain her role as homemaker and mother to her other children, and develop her relationship with the new-born. But there are many risks, and it is essential that she is monitored by a competent adult round the clock, and visited frequently by professional staff. Home treatment is a counsel of perfection and most women will be admitted to a psychiatric hospital, many as an emergency, and usually without their babies. In a few countries, especially Australia, Belgium, France, India, the Netherlands, Switzerland and the United Kingdom, special units allow the admission of both woman and infant. Conjoint admission has many advantages, but the risks to the infant of admission to a ward full of severely ill mothers should not be understated, and the high ratio of nursing staff, required to safeguard the infants, make these among the most expensive psychiatric units. Treatment of the acute episode These mothers require sedation with anti-psychotic (neuroleptic) agents, but are liable to extrapyramidal symptoms, including neuroleptic malignant syndrome. Since the link with bipolar disorder was recognized (about 1970), treatment with mood-stabilizing agents, such as lithium and anti-convulsant drugs, has been employed with success. Electroconvulsive therapy has the reputation of efficacy in this disorder, and it can be given during pregnancy (avoiding the risk of pharmaceutical treatment), with due precautions. But there have been no trials, and Dutch experience has shown that almost all mothers recover quickly without it. After recovery the mother may need antidepressant treatment and/or prophylactic mood stabilizers; she will need counselling about the risk of recurrence and will often appreciate psychotherapeutic support. Prevention There is much evidence that lithium can at least partly prevent episodes in mothers at high risk. It is dangerous during parturition, when pressure in the pelvis can obstruct the ureters and raise blood levels. Started after the birth its adverse effects are minimal, even in breast-fed infants. Causes The cause of postpartum bipolar disorder breaks down into two parts – the nature of the brain anomalies that predispose to manic and depressive