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EXPOSURE TO MIFEPRISTONE IN PREGNANCY

Date of issue: October 2016
Version: 3

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.

Summary

Mifepristone is a synthetic antiprogestogenic steroid and glucocorticoid antagonist which sensitises the myometrium to prostaglandin-induced contractions and softens and dilates the cervix. It is used sequentially with a prostaglandin analogue for medical termination of pregnancy, for cervical ripening before mechanical dilatation, and for induction of labour following intrauterine fetal death.

As would be expected, mifepristone exposure in early pregnancy is associated with an increased occurrence of spontaneous abortion. There are insufficient data to determine if mifepristone exposure in monotherapy is associated with an increased risk of congenital malformation in the fetus. Exposure usually occurs in the context of pregnancy termination, along with a prostaglandin analogue, typically misoprostol, which is independently associated with a spectrum of fetal abnormalities including Möbius syndrome and limb reduction defects. Impact on risk of intrauterine death, preterm delivery, low birth weight, neonatal complications or neurodevelopmental impairment has also not been determined. 

When mifepristone has been used as an abortifacient, completeness of the abortion process should be checked by follow-up scans. As exposure to mifepristone in early pregnancy has abortifacient effects, additional fetal monitoring may be warranted for ongoing pregnancies. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.

This document is regularly reviewed and updated. Only use full UKTIS monographs downloaded directly from TOXBASE.org to be sure you are using the most up-to-date version. The summaries of these monographs are openly available on UKTIS.org.

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 www.toxbase.org.

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 TOXBASE.org or UKTIS.org to ensure you are using the most up-to-date version.