Impact of Plastic Vs. Glass Containers on Hormonal and Growth Outcomes in Preterm Infants Fed Pasteurized Donor Milk: A Randomized Trial Publisher



Hassanvand N ; Hemati Z ; Yazdi M ; Sadeghnia A ; Ahmadi M
Source: Exposure and Health Published:2026

Abstract

Donor human milk (DHM) is prioritized for preterm infant feeding when Mother’s Own Milk (MOM) is unavailable. Its quality may be influenced by container type during handling, pasteurization, and storage. This study aimed to assess the effects of human milk pasteurized and stored in plastic versus glass containers on hormone levels and anthropometric outcomes in preterm infants admitted to neonatal intensive care units (NICUs). In this randomized clinical trial (March 2023–January 2024), 129 preterm infants (26–32 weeks gestational age) admitted to NICUs in Iran were randomized to receive DHM stored in either plastic (n = 65) or glass (n = 64) containers. Participants were randomized into two groups: 65 infants received DHM stored in plastic containers, and 64 received DHM stored in glass containers. After four weeks of feeding, blood samples were collected to evaluate serum levels of Estrogen, growth hormone (GH), thyroid-stimulating hormone (TSH), free thyroxine (FT4), and immunoglobulin A (IgA). Anthropometric measurements were recorded under standardized conditions. FT4 levels were significantly higher in the glass container group (Median [IQR]: 1.36 [1.07, 11.55] vs. 1.2 [1.06, 1.34], p = 0.007). Preterm infants in the glass container group had significantly greater HC at weeks 2 (p = 0.031) and 4 (p = 0.044). Although mean height did not differ significantly between groups at specific time points, a significant group×time interaction (p = 0.027) indicated higher longitudinal growth velocity in the glass container group. The findings of this study suggest that glass containers may better preserve hormonal and nutritional integrity of DHM and support improved growth in preterm infants. © The Author(s), under exclusive licence to Springer Nature B.V. 2026.