(Reuters) - Similac baby formula maker Abbott is expected to face a trial on Monday over claims that its formula for preterm infants used in neonatal intensive care units causes a potentially deadly bowel disease, the second trial out of hundreds of similar lawsuits in the United States.

Lawyers for the company and for Illinois resident Margo Gill will make their opening statements to jurors in St. Louis, Missouri, and the trial is expected to last most of the rest of the month. Gill alleges in the lawsuit that her premature infant child developed necrotizing enterocolitis (NEC) as a result of being fed Abbott's products for premature babies.

NEC, which causes the death of bowel tissue, mostly affects newborns and has a fatality rate of between 15% and 40%. Gill's child survived, but suffers long-term health problems, according to the lawsuit.

Like all of the lawsuits over NEC, the case involves formula and products for fortifying mother's milk given to infants in hospital settings, not ordinary formula available to consumers in stores.

"Specialized formulas and fortifiers, like the one in this case, are considered part of the standard of care by the medical community and, along with human milk, are the only available options to feed premature infants," Abbott said in a statement.

The company said that Gill's child "suffered from a traumatic brain injury in utero and at birth, long before she was fed any Abbott products," and that "no one is to blame" for her condition.

Close to 1,000 lawsuits have been filed against Abbott, Enfamil formula maker Reckitt Benckiser or both in federal or state courts alleging that cow's milk-based formula products for premature infants caused NEC. More than 500 are centralized in an Illinois federal court, with others pending in Illinois, Missouri and Pennsylvania.

The lawsuits claim that the companies failed to warn that infants given their products are at greater risk of NEC compared to infants who are breast-fed or given donor milk or human milk-derived formula.

Reckitt and a lawyer for the plaintiffs did not immediately comment.

The first lawsuit to go to trial, against Reckitt in Illinois, ended with a $60 million jury verdict in March. Reckitt is appealing that verdict and has argued that the plaintiff's case relied on unsound expert testimony.

The litigation has concerned investors. Reckitt's share price fell about 15% after the verdict, and Abbott's about 4%. Both stocks have remained depressed, although analysts at JPMorgan and Barclays have said they believe the companies' ultimate liability is likely to be small.

The NEC Society, a patient-led non-profit organization working to combat the disease, has criticized the lawsuits, saying that "feeding decisions should be made at patients' bedsides, not in courtrooms." The group has no financial or other relationship with Abbott or Reckitt, according to a spokesperson.

The NEC lawsuits are separate from ongoing litigation against Abbott over the shutdown of its Sturgis, Michigan, plant and subsequent recall of batches of baby formula for possible contamination, which contributed to a nationwide formula shortage in 2022. There have been no trials in those cases.