A comprehensive 2026 study found that phthalates, chemicals used to soften plastics, account for over 8% of all preterm births worldwide, contributing to approximately 1.97 million premature deliveries and 74,000 newborn deaths in a single year. These findings, published in the journal eClinicalMedicine by researchers from NYU Langone Health, reveal that the containers we use to store food and water may pose a significant risk to reproductive health, particularly for pregnant women and developing fetuses.

What Are Phthalates and Why Do They Leach Into Food?

Phthalates are synthetic chemicals added to plastics to increase their flexibility, transparency, and durability. Unlike some additives that bond chemically to plastic, phthalates are simply dispersed throughout the material, making them prone to migration. When plastic containers come into contact with food, water, or heat, these chemicals escape the plastic matrix and dissolve into whatever they contain .

This leaching process accelerates dramatically with temperature. In warm climates or when plastic containers are stored in direct sunlight or transported in non-refrigerated vehicles, the rate of chemical migration increases significantly. For pregnant women, even low-level exposure to phthalates can interfere with hormonal signaling, potentially leading to gestational complications and premature labor .

How Does Plastic Food Storage Compare to Glass for Safety?

The fundamental difference between glass and plastic storage containers comes down to chemistry. Glass is made from silica, soda ash, and limestone, creating a material that is chemically inert. This means glass does not react with food or water and does not leach any chemicals, regardless of temperature or storage duration. Laboratories, which demand the highest standards of purity, rely almost exclusively on glass containers for this reason .

Plastic containers, by contrast, present multiple chemical risks. Many large water jugs are made from polycarbonate (recycling code #7) or polyethylene terephthalate (PET, #1). Polycarbonate historically contained bisphenol A (BPA), an endocrine disruptor that can mimic hormones in the body. While many manufacturers have switched to "BPA-free" alternatives like bisphenol S (BPS) or bisphenol F (BPF), research suggests these replacement chemicals may exhibit similar hormonal activity to BPA . Additionally, PET plastic can leach antimony, especially when stored for extended periods or exposed to heat .

The challenge for consumers is that "BPA-free" does not necessarily mean "phthalate-free." A plastic bottle can be free of BPA while still containing phthalates used for flexibility. This distinction is critical, as the 2026 research specifically identified phthalates, not BPA, as the primary driver of preterm birth risk .

How to Reduce Phthalate Exposure in Your Home

• Replace Plastic Food Storage: Transition from plastic containers to glass alternatives for storing leftovers, prepared meals, and other foods. Glass is inert and does not leach chemicals regardless of temperature or storage duration.
• Avoid Microwaving in Plastic: Never microwave food in plastic containers or cover food with plastic film. Heat accelerates phthalate migration. Instead, use ceramic or tempered glass containers that can safely withstand microwave temperatures.
• Eliminate Single-Use Plastic Wraps: Replace plastic film with beeswax wraps or silicone lids, especially for high-fat foods like cheese and meat, which absorb phthalates more readily than other foods.
• Filter Your Drinking Water: Transition from bottled water stored in plastic to point-of-use filtration systems. Water stored in plastic for extended periods, particularly in warm conditions, accumulates higher levels of leached chemicals.
• Choose Solid Personal Care Products: Phthalates are commonly used in liquid shampoos, lotions, and soaps to carry fragrances. Switching to solid shampoo bars and soap blocks reduces plastic packaging and eliminates this source of exposure.

What Does the Research Actually Show About Pregnancy Outcomes?

The 2026 study conducted by researchers at NYU Langone Health analyzed global health data to quantify the impact of phthalate exposure on birth outcomes. The findings are striking: phthalates accounted for over 8% of all preterm births worldwide during the study period. Preterm birth, defined as any delivery before 37 weeks of pregnancy, is a leading cause of infant mortality and long-term developmental complications including respiratory issues, learning disabilities, and chronic health problems .

The research emphasizes that even "replacement" chemicals used in products labeled as alternatives to traditional plastics often carry similar reproductive and developmental risks. This means that simply choosing a "BPA-free" plastic container does not necessarily protect against phthalate exposure .

Why Glass Containers Offer Superior Safety for Food Storage

Beyond chemical inertness, glass containers offer several advantages for food storage. The non-porous surface of glass resists stains and odors, meaning it can be reused indefinitely without degradation. Glass is infinitely recyclable and made from abundant natural materials like sand. While glass production is energy-intensive, its capacity for unlimited reuse and recycling over decades mitigates this initial environmental cost .

Glass also preserves the sensory quality of food and water. Many people report that plastic containers can impart a "plastic" taste to water, especially if exposed to heat. Glass maintains the pure, crisp taste of water and does not alter the flavor of stored foods .

The primary drawback of glass is its vulnerability to breakage from impact and its weight compared to plastic. However, for stationary food storage in kitchens and refrigerators, these limitations are minimal .

What Should Pregnant Women Know About Reducing Plastic Exposure?

For pregnant women, the stakes are particularly high. Phthalate exposure during pregnancy interferes with the body's hormonal signaling, potentially leading to gestational diabetes, preterm labor, and other complications. The 2026 research indicates that reducing plastic reliance during pregnancy is not merely a preference but a public health imperative .

Practical steps include eliminating single-use plastic bottles, replacing plastic food storage containers with glass, and avoiding heating food in plastic containers. These changes are especially important in warm climates, where heat accelerates chemical leaching. Additionally, choosing filtered tap water over bottled water stored in plastic eliminates a major source of chronic phthalate exposure .

The transition away from plastic does not require perfection. Even partial reductions in plastic use can meaningfully lower the body's chemical burden. Experts emphasize that the most effective approach is to eliminate the primary sources of exposure: single-use plastic bottles, plastic food storage containers, and heated plastic containers .