China on Monday said it would allow all married couples to have three children, up from the limit of two, as it further loosened decades of population controls that have left the country in a demographic crisis.

The policy change, announced at a Politburo meeting chaired by Chinese leader Xi Jinping, was aimed at “maintaining national security and social stability” and keeping “our country’s advantages in human resource endowments,” the powerful decision-making body said, according to state news agency Xinhua.

The announcement came as a surprise to many and appeared to reflect alarm among Chinese leaders about growth trends — an issue that has become increasingly politically sensitive.

In May, the results of a once-in-a-decade census showed China’s population growth over the past decade was its slowest since the 1950s, with the population reaching 1.41 billion in 2020 from 1.40 billion in 2019. Average annual population growth over the past decade was just 0.53 percent.

Officials delayed the release of that data, originally slated for April, sparking speculation that China’s population had already begun to shrink. Experts say that a quickly aging population and a shrinking labor force could derail economic growth in the world’s most populous country.

As new data exposed the vulnerabilities in China’s growth model, calls for scrapping restrictions on family size — from demographers to central bank officials and entrepreneurs — have gained urgency.

Yet China’s leaders stopped short of completely dropping the deeply unpopular family-planning regime in place since 1980 — often brutally enforced, through forced abortions, sterilizations and steep fines.

Keeping the limits in place, researchers say, is a way to maintain control.

“It is the same statist and planning mentality,” said Yong Cai, a sociologist at the University of North Carolina at Chapel Hill who studies China’s birth policies.

The new three-child rule “is unlikely to have major demographic effect,” he said. “China should have abandoned its birth planning altogether.”

China’s birthrates have fallen consecutively for four years, to 12 million in 2020, the lowest figure since 1961, when the country was emerging from the grips of mass famine. China’s fertility rate is one of the world’s lowest, at 1.3 births per woman, well below the “replacement rate” of 2.1 births per woman considered necessary to maintain a stable population.

Demographic experts have long said that lifting restrictions alone will not improve the birthrate. In 2016, when China ended decades of the “one-child policy” to allow all couples to have two children, the change did little to encourage couples deterred by the increasingly high costs of raising a family in China’s highly competitive cities.

Others have said the government should change rules that bar same-sex couples and single women from reproductive assistance, such as freezing eggs and accessing sperm banks.

“The three-child policy is a step forward, but the question is: If the two-child policy did not mean people had more children, will that happen under a three-child policy?” said Sun Xiaomei, a professor at China Women’s University.

Officials did not say when the new rules would be implemented.

Without giving specifics, the Politburo on Monday said it would reduce the costs of education, improve maternity care and insurance and provide other support to families on housing and taxes. The almost entirely male political body said it would “protect the legitimate rights and interests” of working women. Officials also said they would gradually raise the country’s retirement age, which is 60 for men and 55 for women.

China’s efforts to encourage its citizens to marry and reproduce have prompted fears that the government will push its citizens to have more children in the same way that it limited them: through coercion. The Politburo on Monday promised to “strengthen the education and guidance” of young married couples, as well as “control bad social customs.”

“The law should respect and protect the people’s reproductive rights and freedom, and let citizens decide for themselves whether to have children or not, and how many,” said Liu Ruishuang, deputy director of the Department of Medical Ethics and Health Law at Peking University.

Online, where the news garnered more than 660 million views on Weibo, the change was met with cynicism and ridicule. One user on the microblog wrote, “Whether you change the policy to five children or eight children, housing prices are still the best sterilization tool.”

One blogger said, “What is this? Producing pigs?” Another wrote, “There’s nothing wrong with changing the policy, I just hope they don’t force it.”

More than 20,000 users responded to a poll posted by Xinhua that having a third child was “absolutely out of the question.” The post was quickly deleted, according to screenshots and comments from Internet users.

Pei Lin Wu in Taipei contributed to this report.