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Non-Narcotic Analgesic Allergy Labels in Pregnancy Drive Suboptimal Care and Adverse Outcomes, With Chang Su, MD
Su described how NNAALs drive management decisions in pregnancy and post partum care.
Unverified drug allergy labels are a well-documented driver of suboptimal prescribing — but a large population-based study presented at the American Academy of Allergy, Asthma & Immunology (AAAAI) 2026 Annual Meeting held in Philadelphia, Pennsylvania, from February 27 to March 2, now extends that harm into the perinatal setting, showing that mothers carrying non-narcotic analgesic allergy labels face significantly elevated risks of eclampsia, preterm birth, and adverse neonatal outcomes compared to those without such labels.1,2
To discuss the findings, we spoke with Chang Su, MD, allergist-immunologist at Yale New Haven Hospital, who conducted the research during her time at University of California San Francisco. The study drew on the Study of Outcomes in Mothers and Infants, a population-based cohort of all singleton livebirths in California between 2016 and 2021 (N = 2,244,210), of which 10,460 were born to mothers carrying non-narcotic analgesic allergy labels (NNAALs). After adjustment for maternal characteristics, NNAALs were significantly associated with increased rates of eclampsia (aRR, 1.5, 95% CI, 1.06-2.12), preterm birth (aRR, 1.21, 95% CI, 1.14-1.28), NICU admission (aRR, 1.17, 95% CI, 1.10-1.25), and neonatal withdrawal syndrome (aRR, 1.51, 95% CI, 1.24-1.84), as well as longer mean infant hospital stays (P <.0001). A decreased rate of large-for-gestational-age infants was also observed (aRR, 0.92, 95% CI, 0.87-0.98). No significant associations were found with maternal preeclampsia, small-for-gestational-age infants, major structural birth defects, or 5-minute APGAR score below 7.
Su highlighted 2 primary mechanisms through which NNAALs appear to be shaping obstetric management — and outcomes — in ways that diverge from clinical guidelines. First, aspirin is recommended for preeclampsia prevention in up to 85% of pregnant patients with relevant risk factors, yet patients carrying an NSAID or aspirin allergy label are substantially less likely to receive it, even when indicated. The significantly elevated eclampsia risk in the NNAAL cohort — a condition that prophylactic aspirin is specifically intended to prevent — is consistent with that gap in guideline-concordant care, though Su was careful to note the association cannot establish causality with certainty. Second, non-narcotic analgesics are the recommended first-line treatment for postpartum pain, and prior studies have shown that patients with NNAALs receive opioids at higher rates and higher doses postpartum — a prescribing pattern with downstream implications in the context of the ongoing opioid epidemic. Together, Su argued, these findings make a strong case that proactive allergy de-labeling should be considered as part of routine prenatal care, not reserved for specialist referral after an adverse event has already occurred.
“People with NNAALs have a higher risk of eclampsia, whether that's because they're not started on aspirin when they need to or due to other reasons… but it does seem like when patients are less likely to receive the recommended preventative care, that that leads to the adverse outcome that it's aiming to prevent,” Su said.
Su has no relevant disclosures to report.
