Most new parents are looking for a way to reclaim even a hint of the sleep they used to get pre-infant. So, a smart bassinet that uses sensors to detect when a crying baby needs pacifying, simulating the sounds and rhythms of the womb, offers an irresistible promise to sleep-strapped parents: another hour or two of shut-eye.

The dream doesn’t come cheap: One of the more popular models, the Snoo retails for US$1,700 , although enterprising parents can score one secondhand from friends, neighbors or relatives whose own children have outgrown it.

But last month, that hand-me-down network was dealt a blow when Happiest Baby, the company that makes Snoo, began charging for access to some of the bassinet’s premium features - features that used to be available to Snoo users indefinitely, at no extra cost. Now, access to the app needed to lock in the bassinet’s rocking level, to track the baby’s sleep and to use the so-called weaning mode, among other features, will cost parents US$20 a month.

The change has angered secondhand users and original buyers alike. On Reddit, the new subscription model has prompted review bombs, group brainstorms for collective action and detailed instructions for outraged parents seeking recourse. Some have taken to filing complaints with the Federal Trade Commission, Better Business Bureau and state-run consumer protection offices.

In June, Happiest Baby sent an email notifying users of changes coming to the app in July. By this month, parents who hadn’t upgraded had fallen into two camps. Some had been bumped down to a lower tier of the app, losing many of the features they had come to rely on. Others, who bought the Snoo directly from Happiest Baby - whether new or “certified pre-loved” - were offered free access to a nine-month premium app subscription for each baby that uses the bassinet.

“Nothing is really changing for anyone who already owns Snoo, who bought their Snoo directly from Happiest Baby or any kind of partner - Amazon, Target - before July 15,” said Lexi Montée Busch, head of marketing at Happiest Baby. “Those people are grandfathered in.”

Andrew Gwin, a father in Huntsville, Alabama, likened the move to buying an iPhone and then being charged to use the camera, or buying a car and having to pay a monthly fee to use the radio. He bought the smart crib for US$600 in March 2023 on Facebook Marketplace and used the Snoo for more than five months with his son, Barrett.

“It was just wonderful,” he said. “The fact that we were able to get him weaning from the Snoo into self-soothing before we moved him to his crib was really key.”

Gwin and his wife, Danica, have another child on the way, arriving in January, but they won’t be paying for the Snoo subscription. He filed a complaint with the FTC in early July.

“It’s clearly a way to punish those who go to the secondhand market and just add a tax on top of the expenses the parents already face,” Gwin said.

The FTC declined to respond to questions about Happiest Baby, saying that it “does not comment on public complaints submitted to the agency”. The Better Business Bureau has given Happiest Baby an F rating. As of Friday, there had been 52 complaints filed by consumers against the company.

Harvey Karp, founder and CEO of Happiest Baby, defended the move as a business necessity. “We don’t have any dollar from the government, we don’t have a dollar from a university,” said Karp, a former paediatrician who created the Snoo after becoming frustrated with the lack of progress in reducing rates of sudden infant death syndrome, or SIDS. “We have to sell products and bring in revenue to be able to get to this goal.”

That goal, according to Karp, is “that everyone will have access to this, and it will be paid for not by your friend, but it will be paid for by your corporation, the government or your insurance company,” the way breast pumps are often covered. He also pointed to Happiest Baby’s efforts to make the Snoo available “in the inner city and in rural areas”. For many parents, however, paying into that ideal is of little comfort to their bottom line.

Kyra Selinger of Saskatchewan bought her Snoo secondhand in October on Facebook Marketplace for C$1,200 . For three months after her daughter, Seattle, was born in May, Selinger used the device to rock her baby to sleep, most often on its “base line” mode, the lowest speed. Then, on Aug 1, she lost access to her settings and sleep log.

“One day, you’re in this routine, you’re kind of in the thick of it, between that six- to 12-week window where you’re learning to put her to sleep,” said Selinger, 30. “And then all of a sudden, what you’ve been doing her entire life has kind of stopped.”

Parents such as Selinger and the Gwins have been drawn to the Snoo since it debuted in 2016 in part for the peace of mind that the bassinet provides. Because babies have to be strapped into the Snoo, they are prevented from rolling over while sleeping, a pattern that can lead to SIDS. In the United States, about 3,400 babies die suddenly and unexpectedly each year, according to the Centers for Disease Control and Prevention.

Ajay Patel, a father and physician in a suburb of Atlanta, said he woke up one morning to his one-month-old daughter crying and found that the Snoo, which he bought for US$600 off Facebook Marketplace, wasn’t activating as it normally would.

“It updated overnight, and it basically changed the settings as our daughter was sleeping,” he said, “which is a little scary, that a company can do that.”

Patel, 38, looked through his inbox and realised that he had received an email from Happiest Baby about changes coming to the app but had filed away the notice as another advertising message he could safely tune out. He could understand putting Happiest Baby’s tips and articles behind a paywall, he said, but found the noise and movement restrictions “unnerving”.

“I don’t want to give a company who would do that my money,” he said. “It has broken trust with parents, at least with us.”

 - NY Times