BEIJING, Feb. 28

The Year of the Pig has turned into the year of the baby.

Chinese hospitals have been submerged in recent months under a tide of pregnant women; newborns are arriving in droves; and companies that manufacture diapers are upping their advertising budgets.

The reason is simple: The Year of the Pig, which began Feb. 18, is a good year to be born.

Since time immemorial, prospective parents have been told, children born under the pig's patronage will benefit from the animal's image as fat, happy and prosperous. Now, couples who schemed to have their babies in these blessed times are hoping for good fortune.

"My family already has two pigs, including my father, and I want to add one more pig," said a pregnant 28-year-old Beijing secretary who identified herself only as Ms. Lian.

"I guess three pigs will also bring luck to us," she explained. "Also, I believe people who are born in the Year of the Pig are honest, because my father is such a person."

The number of couples who calculated to have their babies in this auspicious year has provided a vivid reminder that, however fast China may be transforming its economy and merging with the modern world, the pull of an ancient culture has remained strong among its 1.3 billion people. Physicians say couples who planned to have their children during the Year of the Pig include well-educated urban professionals, as well as farmers' wives who might be expected to be more traditional.

The government's family planning department said it has not yet established a nationwide estimate for how many extra babies will be born in the Year of the Pig. But Beijing hospital officials surveying busy birthing and prenatal care wards predicted a 20 percent increase. Extrapolating that to the 16 million births recorded annually across China in recent years would mean a jump of about 3 million babies.

The birthrate has long been a carefully watched number in China, where the government enforces a one-child policy for most urban families. Premier Wen Jiabao recently declared that the sometimes controversial policy must continue to allow Chinese to benefit from economic progress. But Year of the Pig families did not appear to be contravening the rules -- just choosing this year to have their babies.

Many couples were acting on a belief that 2007 is not only a Year of the Pig, which comes along once every 12 years, but a Golden Year of the Pig, which comes along once every 60 years and showers extra-powerful blessings on those born during its passage. But Ye Chunsheng, a culture researcher at Guangzhou's Sun Yat-Sen University and deputy secretary general of the China Folklore Society, said that belief was mistaken.

"This year is not golden," he said. "It is earthen. The last Golden Year of the Pig was 1971, and the next one should be 2031, with 60 years as the full cycle."

In Chinese tradition, one of 12 animals is assigned as a patron for each year. Besides the pig, there is the dog, which held sway over 2006, and the monkey, snake, horse, dragon, sheep, rooster, mouse, ox, rabbit and tiger. Each animal is supposed to endow children born during its year with special characteristics.

Many people got the impression they were about to live through a Golden Year of the Pig from reports in newspapers and on television, said Xiao Fang, who studies folk culture at Beijing Normal University and is an officer of the Folklore Society. Xiao said part of the hype also came from businesses hoping to cash in on the baby boom.

Chinese companies and subsidiaries that manufacture diapers, baby care oils and infant foods increased their advertising budgets by more than 50 percent for 2007, with much of the extra money to be spent on television spots, according to a survey conducted by the Nielsen Media Research firm.

"But of course, the hype is also based on people's traditional concept of a special year," Xiao added. "The pig in general is considered by Chinese as a representative of fortune and luck, with a mild temper and an honest character, so many Chinese parents believe babies born in this year are lucky . . . and Chinese always like to follow the crowd."

The rush to have children born in the Year of the Pig has put sudden pressure on medical facilities, already strained in China's overburdened health care system. Zhang Weiyuan, deputy director of Beijing Obstetrics Hospital, said that about 600 pregnant women a day have been visiting for prenatal examinations and that the number of births is climbing steadily.

"It's really a burden for the hospital, and now we are discussing how to deal with it," Zhang said.

Already the hospital has opened four extra exam rooms, bringing the total to 12, each capable of handling 100 women, and doubled the size of the waiting room, Zhang said.

Ye Zi, a 30-year-old businesswoman, said she became pregnant eight months ago without any particular desire to see her son-to-be born in the Year of the Pig, but now is suffering long waits and crowding at Beijing Obstetrics Hospital because of the trend.

"The problems of having a piglet baby are already apparent in the hospital, so I can expect that it will be quite competitive for my child to go to school, to look for jobs or even to find a girlfriend," she said.

"But I still think it's great to be born in this year," she added. "I hope this will bring him good luck. The elderly keep on saying that boys born in the Year of the Pig are lucky. I have been hearing this since childhood. It's just a Chinese belief. But I feel very lucky to have a piglet child this year, and if it's the golden pig, so much the better."

Researcher Li Jie contributed to this report.