Safety of herbal medicine in the postpartum period: A hospital-based single-arm, prospective observational study...

Herbal medicines (HMs) are commonly used during the postpartum period in South Korea; however, comprehensive data regarding their safety remain limited. This study aimed to evaluate the safety of HM use among postpartum women through the "SAFEty of HErbal medicine REgistry in Postpartum Care center" (SAFEHERE-PC) study.

A single-arm, prospective observational study was conducted from March to December 2024, enrolling 186 women within six weeks postpartum who were admitted to the postpartum care center of a Korean Medicine hospital. The study monitored adverse events (AEs) during HM use, collecting demographic information, medical history, herbal prescription details, and AE data. Reported AEs were analyzed using the WHO-UMC causality assessment and the Naranjo algorithm.

Of the 186 participants, 4 (2.2 %) experienced AEs following HM administration, all of which were gastrointestinal symptoms (diarrhea, loose stools). Three of the five events were managed with a short course of the herbal formula, and two cases resolved spontaneously without requiring medical intervention. Based on severity and clinical course, the events were classified as mild to moderate. Causality assessment using the WHO-UMC system classified four cases as "possible" and one as "certain", while the Naranjo scale indicated three cases as "possible" and two as "probable" in their association with HM use.

A low incidence of mild gastrointestinal AEs (2.2 % of patients; 0.6 % of prescriptions) was observed, with no serious AEs reported. These findings provide descriptive safety data specific to the formulations and clinical practices used at this hospital-based postpartum care center.

Korean National Clinical Trial Registry Clinical Research Information Service: KCT0009060.