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(Date of issue: December 2012, 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.


Low-dose aspirin (75-300mg/day) is used as an antiplatelet medication to reduce the risk of thrombosis in cerebrovascular disease and myocardial infarction, and in the prevention of pre-eclampsia.  Higher doses of aspirin (up to 4g/day) are used in the control of mild to moderate pain and pyrexia.

Various malformations have been reported following therapeutic maternal use of aspirin during pregnancy, however with the exception of a possible increased incidence of gastroschisis, no specific pattern of malformations has been observed and a causative role for aspirin has not been proven.

The available data on fetal outcome following aspirin overdose during human pregnancy are very limited.  There are two retrospective case reports of congenital malformation and two of intrauterine death after maternal overdose with aspirin.  Prospective outcome data collected by UKTIS on 90 women who overdosed with aspirin at any stage in pregnancy showed no increase in overall congenital malformation rate.  However, gastroschisis was reported in one of 19 live-born infants exposed during the first trimester, and hypospadias in another.  An increase in risk of fetal malformation after first trimester maternal aspirin overdose can therefore not be excluded, particularly given the possible association between therapeutic aspirin exposure and gastroschisis. 

Exposure to NSAIDs after 30 weeks of pregnancy is associated with an increased risk of premature closure of the ductus arteriosus and oligohydramnios.  These effects are related to the inhibitory effect of NSAIDs on prostaglandin activity and may also be a concern with high dose aspirin.  The incidence and severity of premature closure of the ductus arteriosus appears to be dose-related and increases with advancing gestational age beyond 30 weeks.  Early obstetric or fetal medicine input is recommended for cases of aspirin overdose in the third trimester as early delivery or additional monitoring may be indicated.

Appropriate maternal treatment of aspirin overdose is important to reduce the risk of salicylate toxicity in both the mother and the fetus.  There are no published guidelines on the management of aspirin overdose in pregnancy and treatment should be as for the non-pregnant patient.  Additional fetal monitoring may be warranted following maternal overdose of aspirin.  Discussion with UKTIS is recommended in all cases. 

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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.