FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later because they can result in low amniotic fluid

The US FDA is recommending avoiding NSAIDs in pregnant women at 20 weeks or later during pregnancy, as their use during this period may cause foetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment.

SPS commentary:

In the US, NSAID prescribing information currently recommends avoiding the use of NSAIDs at 30 weeks and later in pregnancy because of the additional risk of premature closure of the foetal ductus arteriosus. The FDA is now recommending that they be avoided from 20 weeks gestation onwards, after a review of the literature noted that although oligohydramnios is mostly observed during the third trimester, there are multiple reports suggesting an earlier onset, around 20 weeks of gestation.

If treatment is deemed necessary between 20 and 30 weeks, use should be limited to the lowest effective dose for the shortest duration possible, and ultrasound monitoring of amniotic fluid should be considered if NSAID treatment extends beyond 48 hours.

In the UK, use of NSAIDs is contraindicated during the last trimester of pregnancy, and should not be used during the first two trimesters unless the potential benefits outweigh the potential risks to the foetus. The prescribing information for various prescription NSAIDs notes that use of all prostaglandin synthesis inhibitors during the third trimester may expose the foetus to renal dysfunction, which may progress to renal failure with oligohydramnios, as noted by the FDA.

Source:

US Food and Drug Administration