Emily Black of Pikesville set out one afternoon this week to buy formula for her infant son. Four hours and five stores later, she still hadn’t found it.

“There’s pretty much been a shortage since he was born, but it’s just gotten progressively worse,” said Black, whose 5-month-old son, Liam, only tolerates a specific brand of formula that’s gentle on his stomach. She has a few weeks worth of formula at home, but is frequently searching to keep stocked.

After months of supply chain disruptions, a national shortage of baby formula recently intensified, leaving parents panicked about how to feed their babies. Families are trekking to faraway stores, searching online retail sites and trading the very latest information about which local shelves have anything. The challenge is especially acute for those who don’t have transportation or who rely on assistance programs such as WIC, which only covers certain brands.

Amid pressure to address the problem, President Joe Biden on Thursday spoke with leaders of formula manufacturers Reckitt and Gerber, as well as Walmart and Target, about efforts to restock. The White House says it will monitor possible price gouging and work to increase the formula supply through increased imports. Most baby formula — 98% — is domestically made.

Sen. Chris Van Hollen of Maryland was among Senate Democrats who wrote Friday to the Infant Nutrition Council of America, a trade group, calling upon member companies to “do all you can to increase infant formula production and distribution, and prevent future supply chain disruptions.”

For now, the situation is urgent.

“We should really be coming together as a community to make sure that the people who need it have what they need,” said Ana Rodney, the founder and executive director of MOMCares, a nonprofit doula program that supports Black mothers in Baltimore whose babies are in the NICU.

Samantha Berlin and her son Jaxson, age 5 months, have an 18-day supply of the special formula he needs due to allergies amid a national shortage of baby formula. (Barbara Haddock Taylor/Baltimore Sun)

As it was getting harder to find formula earlier this year, MOMCares ordered a bulk shipment in February, Rodney said. But as soon as the formula arrived, they got word of a major recall by Abbott Nutrition, maker of popular brands including Similac.

MOMCares had to send back most of the formula, which was “devastating,” Rodney said.

The Abbott recall stemmed from concerns about bacterial contamination at a Michigan plant that federal officials say may have contributed to the deaths of two babies. It came amid existing shortages related to the pandemic.

At the Baltimore nonprofit ShareBaby, which distributes diapers and other essentials to families in need, front line workers are hearing stories of people feeding their babies less frequently or watering down formula, which can lead to serious health problems, said executive director Amina Osman Weiskerger.

ShareBaby and its partners work with many families who lack reliable transportation and whose neighborhoods don’t have big-box retailers or full-service grocery stores, Weiskerger said.

“All of those things make it … especially challenging for needy families in our area,” she said. “The need is tremendous.”

About half the formula nationwide is purchased by WIC participants, according to the federal government. The Biden administration says it’s working with states to make it easier for WIC participants to buy formula.

Maryland expanded WIC formula options in February “as soon as we received federal authorization,” state health department spokesman Chase Cook said in an email.

There has been a varying level of formula shortage throughout the pandemic, and as an essential product, “any fluctuations in supply chain capacity can lead to a worsening shortage as consumers stockpile in anticipation of future shortages,” said Tinglong Dai, a professor at Johns Hopkins University’s Carey Business School.

“You have very little room for error in this kind of vulnerable supply chain situation,” and now the industry is experiencing a capacity reduction as a result of the problems at the Michigan facility, Dai said in an email.

He added that “consumers have little choice because trade restrictions prevent them from easily switching to baby formula from European countries or Canada or Australia.”

“When a supply disruption meets a highly inflexible and vulnerable supply chain, we see a perfect storm,” he said.

That storm is leaving parents overwhelmed.

“It’s your job to protect them and provide for them,” said Dan Richardson of Windsor Mill, who has found bare shelves while looking for formula for his 8-month-old daughter, Isabella. “It’s very, very stressful as a parent.”

The formula shortage is a hot topic on online parenting forums, and new Facebook groups are popping up for parents to post photos showing which local stores are stocked.

Richardson shipped formula to a father who needed it in Massachusetts, and he has relatives in New Jersey on the lookout for Isabella’s brand of formula.

“It takes a village,” he said.

Black, the Pikesville woman, recently dropped off formula for another mother.

“She was down to her final three scoops and didn’t know how she was going to feed her baby,” Black said.

Formulas for babies with special nutritional needs have been especially difficult to find.

“We’ve been living off PurAmino samples,” said Glen Arm resident Samantha Berlin, referring to a hypoallergenic formula.

Her 5-month-old son, Jaxson, was diagnosed last month with allergies to soy and dairy. He screamed in pain without the right formula.

“I don’t think people understand that we can’t just switch,” Berlin said.

As she searches online for specialty formula, she said she is seeing “ridiculous” price differences between some retailers.

It is a scary situation for parents, said Dr. Ashanti Woods, a pediatrician with Mercy Family Care Physicians in Baltimore.

“We empathize with our families,” he said.

Woods urged parents to speak with their doctors if they are having problems getting formula. He is encouraging families to try different brands when possible, and to check which days stores receive shipments.

Woods warned against giving babies diluted, homemade or toddler formula, as well as whole cow’s milk.

Jonelle Lund, a registered nurse and lactation consultant, said she has recently seen an uptick in mothers who want to relactate — the process of resuming milk production after stopping — as a result of the formula shortage. Her business, LavaBaby Lactation, serves the Baltimore and central Pennsylvania areas.

Relactation involves pumping every few hours to reestablish breast milk production.

“It’s a big time commitment and I think that’s important for women to understand,” Lund said.

On social media, some have questioned why mothers don’t turn to breastfeeding to deal with the formula shortage.

But many adoptive families rely on formula, and many women struggle with breastfeeding — or have medical or personal reasons for choosing not to.

At MOMCares, the Baltimore nonprofit serving Black NICU mothers, women have endured serious medical conditions or are taking medications that interfere with their ability to breastfeed, Rodney said.

She noted racial disparities in breastfeeding, including lower rates of breastfeeding initiation for Black mothers at the hospital.

“There’s not as much support and unfortunately there is bias that goes into the support that is available at the hospital,” Rodney said.

And “breast milk is not free,” Woods, the Mercy pediatrician, said. Breastfeeding “is physically taxing, is emotionally taxing, and the owner of that breastmilk has to go through a lot.”

The Associated Press contributed to this article.