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(Date of issue: January 2015, Version: 2)

This is a UKTIS monograph for use by health care professionals. For case-specific advice please contact UKTIS on 0344 892 0909. To report an exposure please download and complete a pregnancy reporting form. Please encourage all women to complete an online reporting form.

A corresponding patient information leaflet on olanzapine use in pregnancy is available at


Olanzapine is an atypical antipsychotic used in the treatment of schizophrenia, manic episodes and recurrence in bipolar disorder.

Although olanzapine exposures are included in a number of studies which report on fetal outcome of women exposed to various antipsychotics, often no separate analysis for olanzapine was carried out.

Human pregnancy data for olanzapine are thus limited. Although the little data that are available do not suggest an increased risk of congenital malformation, spontaneous abortion, low birth weight, preterm delivery or intrauterine death, increased risks for some of these outcomes have been reported for antipsychotics as a group, and olanzapine has not been adequately studied to state that there is no increase in risk. 

Maternal hyperglycaemia and increased fetal growth have been reported with use of olanzapine in pregnancy, although data are conflicting. Given that weight gain is a recognised complication of olanzapine therapy and that both complications are associated with an increased risk of adverse pregnancy outcome, additional maternal and fetal monitoring may be prudent until more robust data are available.

Exposure in later pregnancy has been associated with a significantly increased risk of neonatal complications, although an increased incidence of neonatal complications has also been reported in the offspring of unmedicated women with psychotic illnesses. Thus the relative contributions of the underlying maternal condition and specific drug treatments have not been clearly defined. 

Use of olanzapine throughout pregnancy or near delivery has been associated with withdrawal symptoms in the neonate and/or poor neonatal adaptation syndrome (PNAS). These symptoms are likely to be more severe in infants exposed in utero to more than one CNS acting drug. Delivery should be planned in a unit with neonatal intensive care facilities.

It is important to ensure that maternal mental health is treated appropriately. Where a patient is stabilised on olanzapine, either prior to conception or during pregnancy, the risk of discontinuing or changing medication, or reducing the dose, should be carefully weighed against the risk of relapse of the maternal condition. Where clinically appropriate, clinicians are encouraged to discuss the advantages and disadvantages of continued olanzapine use during pregnancy with the patient. Where the benefit of continued treatment is considered to outweigh any potential or known risks, olanzapine may be prescribed for use in pregnancy.

This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from or to be sure you are using the most up-to-date version.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to health care professionals at

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from or to ensure you are using the most up-to-date version.