There are limited published data on fetal outcomes following paracetamol overdose during human pregnancy, however the information available does not suggest an increased risk of congenital malformation or fetal loss in the absence of severe maternal toxicity. There is evidence that the fetal liver begins to metabolise paracetamol from 18 weeks gestation onwards, therefore the fetus may also be at risk for hepatotoxicity following maternal paracetamol overdose at and beyond this stage.
Maternal treatment of paracetamol overdose should be as for the non-pregnant patient. There is evidence linking a delay in treating a pregnant patient with N-acetylcysteine with increased fetotoxic effects. Treatment with N-acetylcysteine should not be withheld on the basis of pregnancy. Where treatment with N-acetylcysteine is clinically indicated, current weight up to a maximum of 110kg should be used to calculate dosing.
Maternal toxicity as a result of paracetamol overdose is likely to be a major determinant of the risk posed to a developing fetus. However, due to limitations in the available data, it is not currently possible to state that an absence of maternal toxicity excludes the possibility of adverse pregnancy or neonatal outcomes.
In general, maternal paracetamol overdose would not usually be regarded as medical grounds for termination of pregnancy. The requirement for fetal monitoring should be decided on a case-by-case basis. Other risk factors may 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.
NOTE: This monograph refers only to paracetamol overdose in pregnancy. For therapeutic use of paracetamol in pregnancy please refer to the document ‘Therapeutic use of paracetamol in pregnancy’.
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 NHS health care professionals who are logged in.
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.