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Date of issue: March 2019, Version: 2

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

Naproxen is a non-steroidal anti-inflammatory drug used primarily for the treatment of pain and inflammation in rheumatic disease and other musculoskeletal disorders.

Use of NSAIDs in pregnancy has been associated with an increased risk of miscarriage, persistent pulmonary hypertension of the newborn (PPHN), oligohydramnios, premature closure of the ductus arteriosus DA, structural cardiovascular defects and a number of other congenital anomalies, including orofacial clefts. However, the available data are limited, confounded and often conflicting; further research is therefore required to define the risk of these outcomes more accurately.

Ten studies which collectively report more than 5,000 pregnancies have investigated the fetal effects of maternal naproxen use in pregnancy. Conflicting findings have been reported relating to the risks of miscarriage and some specific congenital malformations. However, it is possible that this is a result of data confounding and further studies are required.

Exposure to NSAIDs after 30 weeks of gestation is associated with an increased risk of premature closure of the DA and oligohydramnios. These effects are mediated by the inhibitory effect of NSAIDs on prostaglandin production. There are conflicting findings regarding the risks of PPHN following antenatal use of NSAIDs. Further evidence is therefore required before this possible association can be confirmed. Where published data concerning the fetal effects of gestational exposure are unavailable or limited, a possible class effect for these associations should be considered for all NSAIDs.

Where clinically indicated, treatment with naproxen in the first or second trimester may be considered. Naproxen should, where possible, be avoided during the third trimester. However, in circumstances where the maternal clinical condition requires treatment with naproxen during the third trimester, discussion with a Fetal Medicine Unit regarding fetal monitoring for oligohydramnios and neonatal monitoring for ductus arteriosus patency is recommended.

Please refer to the overview monograph ‘Use of non-steroidal anti-inflammatory drugs (NSAIDs) in pregnancy’ for more information. 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.