A Japanese Pregnant Woman With Treatment-Resistant Schizophrenia Who Continued Clozapine With Blood Concentration Monitoring During the Perinatal Period and Had a Healthy Baby: A Case Report.

BACKGROUND

Clozapine is known to improve the social functioning of patients with treatment-resistant schizophrenia (TRS). In Japan, there are few reports on pregnancy and childbirth in patients treated with clozapine, and information on its effects on the fetus and mother is limited.

CASE PRESENTATION: A woman in her 30s with TRS planned her pregnancy while using clozapine (300 mg/day). From around 32 weeks of gestation, she noticed decreased fetal movement and fetal heart rate abnormalities were observed. At 35 weeks of gestation, her clozapine blood concentration was 594 ng/mL (clozapine blood concentration/clozapine dose: C/D ratio, 1.98), which was slightly high, so the dose was reduced to 275 mg/day. With the continuation of clozapine, the mother's psychiatric symptoms remained stable, and she delivered a healthy baby vaginally at 38 weeks of gestation. The clozapine blood concentration increased just before delivery (C/D ratio 2.35) but rapidly decreased after delivery (C/D ratio 1.69). The newborn was discharged in good condition on the fourth day of life.

CONCLUSION

This case suggests that clozapine can contribute to pregnancy and live birth in TRS patients, but the blood concentration of clozapine may increase more than expected in late pregnancy, necessitating consideration of dose reduction.