studied. According to one systematic review evaluating 37 different reports of antipsychotic use in 206 infants, olanzapine has the strongest supporting evidence for low infant exposure through breastmilk, while fewer reports support a similarly low exposure for quetiapine and ziprasidone use. Chlorpromazine also demonstrates minimal transference to the infant through breastmilk. There is currently no consensus to the safety or level of lithium present in breastmilk, though several guidelines and reviews do not consider it an absolute danger to the infant which should exclude its use. Several reports describe safe use of lithium during breastfeeding with no noticeable effects in the infant, though any lasting effects have not been well-studied. As in adults, lithium use with breastfeeding infants requires careful monitoring of the child for serum levels, dose adjustment, and any side effects; thus, the ability of the patient to maintain follow-up care should also be taken into consideration when lithium may be used. Short-acting benzodiazepines, like lorazepam, are preferred from this class of drugs as they demonstrate lower levels passed through breastmilk and no reported side effects in infants. Prognosis and Outcomes Symptoms may last for a variable length of time (up to one year in 25% of cases) despite adequate treatment. Despite most individuals (50-80%) experiencing a relapse episode and development of chronic psychiatric disorders (such as bipolar spectrum disorder), these same individuals are expected to be able to resume normal activities of their daily life with the same level of function as previously experienced. Of the minority of persons who experience PPP and choose to have another pregnancy, evidence has shown that about 33% will have a repeat psychotic episode. Other factors that contribute to poorer prognosis include an experience of PPP that's limited to the postpartum period (rather than a diagnosis of bipolar disorder, for example), longer initial psychotic episodes, and a higher severity in the initial episode. Infanticide (or filicide) is thought to occur in 1 to 4% of PPP cases, and some evidence suggests that these incidents are more commonly related to PPP episodes that feature more depressive symptoms. Epidemiology PPP is rare, reported to occur in about 1 to 2 of every 1000 childbirths (0.9 to 2.6 per 1,000). Reported cases are thought to underestimate the actual occurrence of PPP due to the probability of some individuals avoiding hospitalized care to avoid separation from their child (particularly in locations with no mother-baby units)