# Anaphylaxis-induced premature uterine contractions: a case report and literature review

## TL;DR

A pregnant woman experienced uterine contractions after an allergic reaction to a snack, suggesting that anaphylaxis can trigger preterm labor.

## Contribution

This case report provides evidence that anaphylaxis can induce uterine contractions and preterm labor in the absence of infection or inflammation.

## Key findings

- Uterine contractions resolved after treating anaphylaxis with antihistamines and epinephrine.
- Skin-prick test confirmed a type 1 hypersensitivity reaction to the strawberry-coated biscuit.
- The case supports the hypothesis that maternal allergic reactions can trigger preterm labor.

## Abstract

Preterm labor is caused by multiple etiologies, including intra-amniotic infection and/or intra-amniotic inflammation, vascular disorders, cervical disease, decidual senescence, and breakdown of maternal–fetal tolerance. Accumulating evidence in vivo and in vitro has shown that an allergic reaction, including anaphylaxis, can induce preterm uterine contractions. This report describes a case of a pregnant woman who developed anaphylaxis and regular uterine contractions after the ingestion of a strawberry-coated biscuit. We also review the mechanism of allergic reaction (hypersensitivity)-induced preterm labor.

Case presentation

A 31-year-old woman (gravida 1, para 0) at 30+2 weeks of gestation was admitted to the labor and delivery unit with regular uterine contractions and anaphylactic symptoms after she ingested a strawberry-coated biscuit as a snack. The uterine contractions resolved after the treatment of anaphylaxis by administering antihistamines and epinephrine. The patient subsequently delivered at 39+3 weeks of gestation. The amniotic fluid profile showed no infection or inflammation. A postpartum skin-prick test confirmed a positive type 1 hypersensitivity reaction to the strawberry-coated biscuit.

We report a case of anaphylaxis-induced uterine contractility in which uterine contractions subsided after the treatment of anaphylaxis. The absence of intra-amniotic infection and/or intra-amniotic inflammation and the cause of the anaphylaxis were confirmed. Our findings indicate that maternal allergic reactions may be one of the mechanisms of preterm labor.