later, based on myxoedema, hypoglycaemia or Addisonian crisis. But these patients can also develop acute and recurrent psychoses, even as early as the puerperium. Water intoxication Hyponatraemia (which leads to delirium) can complicate oxytocin treatment, usually when given to induce an abortion. By 1975, 29 cases had been reported, of which three were severe or fatal. Urea cycle disorders Inborn errors of the Krebs-Henseleit urea cycle lead to hyperammonaemia. In carriers and heterozygotes, encephalopathy can develop in pregnancy or the puerperium. Cases have been described in carbamoyl phosphate synthetase 1, argino-succinate synthetase and ornithine carbamoyltransferase deficiency. Anti-NMDA receptor encephalitis The most recent form of organic childbearing psychosis to be described is encephalitis associated with antibodies to the NMDA receptor; these women often have ovarian teratomas. A Japanese review found ten reported during pregnancy and five after delivery. Other organic psychoses with a specific link to childbearing Sydenham's chorea, of which chorea gravidarum is a severe variant, has a number of psychiatric complications, which include psychosis. This usually develops during pregnancy, and occasionally after the birth or abortion. Its symptoms include severe hypnagogic hallucinations (hypnagogia), possibly the result of the extreme sleep disorder. This form of chorea was caused by streptococcal infections, which at present respond to antibiotics; it still occurs as a result of systemic lupus or anti-phospholipid syndromes. Only about 50 chorea psychoses have been reported, and only one this century; but it could return if the streptococcus escapes control. Alcohol withdrawal states (delirium tremens) occur in addicts whose intake has been interrupted by trauma or surgery; this can happen after childbirth. Postpartum confusional states have also been reported during withdrawal from opium and barbiturates. One would expect acquired immunodeficiency syndrome (HIV/AIDS) encephalitis to present in pregnancy or the puerperium, because it is a venereal disease that can progress rapidly; one case of AIDS encephalitis, presenting in the 28th week of gestation, has been reported from Haiti, and there may be others in countries where AIDS is rife. Anaemia is common in pregnancy and the puerperium, and folate deficiency has been linked to psychosis. Incidental organic psychoses The psychoses, mentioned above, all had a recognized connection with childbearing. But medical disorders with no specific link have presented with psychotic symptoms in the puerperium; in them the association seems to be fortuitous. They include neurosyphilis, encephalitis including von Economo's, meningitis, cerebral tumours, thyroid disease and ischaemic heart disease. Society and