You need to be logged in to see the full monograph.


Date of issue: August 2018, Version: 1

bumps logo
A corresponding patient information leaflet on EXPOSURE TO TOY SLIME IN PREGNANCY is available.

Slime toys consist of viscous, brightly coloured ‘slime’, usually in a plastic pot. These products often contain borax as a component to maintain their texture. In July 2018 it was widely reported in the media that several brands of toy slime contained higher than EU-permitted levels of boron (300mg/kg) owing to their borax content. Borax reacts with hydrochloric acid (e.g. in the stomach) to form boric acid.

There are no studies specifically investigating the fetal effects of handling toy slime in pregnancy. A single small study found that women exposed topically in early pregnancy to boric acid were not at increased risk of having an infant with a birth defect, although the data are extremely limited. In general, dermal absorption of boron compounds is expected to be minimal as long as skin is intact. Risk of maternal and fetal toxicity following dermal contact with toy slime is therefore likely to be low, and no active management or investigation is advised for pregnant women without symptoms of toxicity. Avoidance of further handling of toy slimes identified as having elevated levels of boron is recommended as a precaution.

A study of women ingesting boron compounds via drinking water found no associations between blood levels and the risks of spontaneous abortion, stillbirth, infant congenital anomaly, preterm birth, low infant birth weight or neonatal death. However, ingestion of excessive amounts of some boron compounds can lead to poisoning associated with diarrhoea, vomiting, and in severe cases, kidney injury, widespread dermatitis and exfoliation, and CNS effects including coma and convulsions. Pregnant women who have ingested toy slime and who experience symptoms suggestive of toxicity should be managed according to the general guidance for non-pregnant patients on Maternal toxicity is likely to be the major determinant of risk to the fetus. Contrary to media reports, animal studies have not conclusively demonstrated that ingestion of boric acid is associated with birth defects in the offspring in the absence of maternal toxicity. As there are no human pregnancy data relating to poisoning with boron compounds, review and follow-up by a specialist in fetal medicine is recommended for pregnant women who have experienced boron toxicity. Due to the lack of data, the possibility of adverse fetal effects cannot be completely excluded in the absence of maternal symptoms.

Handling of toy slime at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy. However, other risk factors which may independently increase the risk of adverse pregnancy outcome may be present in individual cases. Clinicians are reminded of the importance of considering of such factors when performing case-specific risk assessments. Where exposure is associated with maternal toxicity, additional fetal monitoring may be advised and will need to be considered on a case-by-case basis.

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.

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 to ensure you are using the most up-to-date version.