From 20 weeks of pregnancy, do not take NSAID painkillers such as ibuprofen on your own

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In October 2020, the US Food and Drug Administration issued a safety warning that NSAID use at around 20 weeks of pregnancy or later can cause fetal kidney problems and low amniotic fluid. It covers prescription and over-the-counter products, including aspirin, ibuprofen, naproxen, diclofenac, and celecoxib. Reviewing adverse-event reports through July 2017, the FDA identified 35 serious cases of low amniotic fluid or kidney dysfunction in newborns. Five newborns died, all with neonatal kidney failure. In published reports, low amniotic fluid usually resolved within 72 hours to six days after the drug was stopped. The FDA advises avoiding NSAIDs from 20 weeks unless specifically recommended by a clinician. Clinician-prescribed low-dose aspirin at 81 mg for certain pregnancy conditions is exempt. The FDA identifies other possible treatments for pain or fever, such as acetaminophen; consult a pharmacist or clinician first.

The FDA points out that many over-the-counter medicines for colds, influenza, and insomnia also contain NSAIDs, so check the ingredients. Earlier US over-the-counter labeling warned only about the last three months of pregnancy; this warning brought the threshold forward to about 20 weeks. For low-dose aspirin to prevent preeclampsia, see entry 27-5. The evidence is rated B because the figures come from adverse-event reports, without a denominator of everyone exposed who had no problem. The medium benefit rating is a judgment: the outcomes are serious but uncommon.

U.S. Food and Drug Administration (2020-10-15). FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later because they can result in low amniotic fluid. Drug Safety Communication. https://www.fda.gov/drugs/drug-safety-and-availability/fda-recommends-avoiding-use-nsaids-pregnancy-20-weeks-or-later-because-they-can-result-low-amniotic