USE OF NAPROXEN IN PREGNANCY

PLEASE BE AWARE: The advice about use of NSAIDs in pregnancy has recently changed. It is now recommended that prolonged use of NSAIDs should be avoided after 20 weeks of pregnancy (rather than the 30 weeks discussed throughout this document). For more details, please see the information from the MHRA here. This document is currently under review, and will be updated as soon as possible to include the new advice.

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.