Ms. A had a history of bipolar disorder and developed postpartum psychosis after her first child was born. She responded to lithium and risperidone. After the delivery of a second child while taking lithium, she again required risperidone (1.5 mg/day) for mood instability and obsessive ruminations about harming her baby. She had trace cogwheeling but no other extrapyramidal symptoms. She did not breast-feed, but she was amenorrheic for several months. Her prolactin level was 164.5 ng/ml. Brain magnetic resonance imaging showed no evidence of a pituitary microadenoma. Two weeks after she stopped taking risperidone, her prolactin level returned to normal, and she menstruated 1 week later. Because her ruminations returned, she was given oral ziprasidone, starting at 20 mg b.i.d., increased over 2 weeks to 60 mg b.i.d. for 3 weeks, then lowered to 100 mg at bedtime for 2 weeks because of sedation. Her ruminations disappeared, but she developed 1+ cogwheeling, tremor, and masked facies and did not menstruate; her prolactin level rose to 124 ng/ml.

Ms. A was switched to quetiapine (400 mg/day) with resolution of extrapyramidal symptoms and a decrease in her prolactin level to 8.2 ng/ml. Her menses resumed within 3 weeks of stopping ziprasidone and remained regular for at least a year. Her prolactin level remained normal.