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(Date of issue: December 2017, 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.


Organophosphates (OPs) are esters of phosphoric acid widely used as domestic and industrial insecticides and pesticides. OPs are also used in chemical warfare as nerve agents. OPs are often diluted in a hydrocarbon solvent and exposure can occur from ingestion, inhalation, dermal and ocular exposure. 

Numerous studies have raised concerns about the possible reproductive effects of chronic low dose OP exposure as a consequence of exposure to pesticides in general due to residential or occupational proximity to agricultural areas. 

Data on acute OP exposure/poisoning in pregnancy are limited to case reports. An increased incidence of congenital malformations has not been reported, however information following first trimester exposure is limited and insufficient to assess the risk adequately. Given the lack of data and the possible adverse associations reported with chronic, low dose exposure to pesticides in general, an increase in risk cannot be ruled out. Where maternal toxicity is present, particularly when exposure occurs close to term or delivery, there may be a risk of neonatal toxicity.

There are no guidelines regarding the treatment of OP poisoning during pregnancy. Maternal toxicity following OP exposure is likely to be a major determinant of risk to the fetus. Management of the pregnant patient should be the same as for the non-pregnant patient.  Where a specific antidote is clinically indicated this should not be withheld on account of pregnancy.

Where exposure to OPs has occurred in pregnancy, enhanced maternal and fetal monitoring may be warranted. Discussion with UKTIS is recommended.

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

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.