But for those who take regular baby formula products, pediatricians believe there are options.
"It's a scary thought to not know what you're going to feed your child," said Bianca Rafael, a new mom living in Los Angeles.
The scramble for baby formula overshadows the joy of being a new mother, and she said her 2-month-old named Emma is always hungry.
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"My anxiety has been skyrocketing," she said. "Just because we don't know what's going to happen."
However, parents have options. According to Huntington Health Physicians pediatrician Dr. John Rodarte, if your baby takes a regular formula, you can switch to another brand.
If you have no alternative and your child does not use a specialty product, the American Academy of Pediatrics said you could feed them whole cow's milk.
"From six months and above, you can use cow's milk for a short period of time," he said. "Again, that's the key not to have it ongoing, but for short periods of time. Maybe for a few days. Maybe a few weeks even."
Plant-based alternatives are not recommended for babies under a year or infants with certain medical conditions.
Soy milk fortified with protein and calcium may be an option for babies close to a year old, but only for a few days or during an emergency. Plus, U.S. Surgeon General Vivek Murthy is warning parents to never water down formula.
"Watering it down changes the electrolytes," said Rodarte. "When you change the electrolytes, you actually put your infant at risk for sleep, things like seizures as well."
Murthy adds never to make your own formula at home or use toddler formula to feed infants.
If you're stuck, Rodarte recommends asking other moms for any breast milk surplus or trying a breast milk bank.
However, for baby Emma, that's not an option.
"She does have a milk protein allergy," said Rafael. "So they just switched her over to the special formula."
The L.A. mom recently found two cans of the dairy-free formula Emma needs. Until more stock is available, she said families should look out for each other.
"Keep your heads up and try your best. We're all in this together," she said.
Of course, always speak with your pediatrician before trying anything new.