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Date of issue: May 2024, Version: 4.1

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A corresponding patient information leaflet on USE OF NITROFURANTOIN IN PREGNANCY is available.

Nitrofurantoin is an antibiotic used for the treatment and prophylaxis of acute or recurrent uncomplicated lower urinary tract infections (UTIs) and pyelitis. It is specifically indicated for the treatment of infections due to susceptible strains of Escherichia coli, Enterococcus, Staphylococcus, Citrobacter, Klebsiella, and Enterobacter.

There is no strong evidence of an association between in utero nitrofurantoin exposure and an overall increased risk of congenital malformation. While individual studies have suggested possible increased risks of hypoplastic left heart, talipes, hypospadias, an/microphthalmia, atrial septal defect, and cleft lip/palate, no pattern of defects is evident, the studies are limited by methodology, and ongoing research is required to confirm or refute these findings. The increase in risk, if any, of congenital malformation following exposure to nitrofurantoin is likely to be small, given that systemic absorption and transfer to the fetus is low.

No statistically significant increased risks of miscarriage, stillbirth, low birth weight, or preterm delivery have been identified, although data are limited for some of these outcomes. An increased incidence of neonatal jaundice has been observed in infants exposed to nitrofurantoin in the month preceding delivery.

Nitrofurantoin in the non-pregnant patient can, in rare cases, cause serious adverse reactions, including peripheral neuropathy, pulmonary toxicity, and fatal hepatic injury. It has also been associated with haemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Nitrofurantoin use is generally avoided during labour and delivery because of the theoretical possibility of haemolytic anaemia in the neonate due to immature erythrocyte enzyme systems.

Guidance on UTI in pregnancy suggests immediate antibiotic treatment, with nitrofurantoin as the recommended first-line option unless contraindicated or not tolerated. Treatment should be reviewed if culture and sensitivity testing of urine sampled before antibiotics were started suggests a more suitable alternative. Any possible risks to the fetus from the drugs used to treat maternal UTI should be weighed against the potential adverse effects for the mother and fetus from an untreated infection. Use of nitrofurantoin during the third trimester of pregnancy is not recommended due to a theoretical risk of haemolytic anaemia in the neonate owing to immature erythrocyte enzyme systems. However, this risk should be carefully weighed against the potential benefit of treatment, particularly if culture and sensitivity results support the use of nitrofurantoin and alternative antibiotics are unsuitable.

Exposure to nitrofurantoin at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, 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.

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.