"I found there are many pregnant women this year," said local resident Jiang Yan. "I know friends, co-workers and other people working in my office building are going to have kids."

"Some of them did tell me they want to give birth to a 'golden pig baby' for the good luck."

The lunar calendar gives each year one of 12 zodiac signs and years rotate through the five elements - gold, wood, water, fire and earth.

Children born when the Year of the Pig coincides with the element of gold, something that happens every 60 years, are said to be blessed.

The expected baby boom is causing headaches for doctors.

"Pregnant women will be given a number first every morning and wait for a check," said a doctor from Changning District Maternity and Child Health Hospital, adding that every day the hospital has 20 newly pregnant women booked for their first check.

In normal years, women don't need to take a number to get a health exam, the doctor said.

A pregnant woman who identified herself as Yueyue said she learned about the "Golden Pig Year" from her mother.

"I cannot tell whether it is true or not," Yueyue said. "But I chose to believe it rather than miss a good opportunity."

The Shanghai Population and Family Planning Commission predicted that 131,000 babies will be born in the city this year, up from 123,901 last year. The number will rise to about 137,000 next year and peak in 2015 at 160,000.

Some city officials worry that the baby boom may result in a series of social problems, with too many children competing for spots in schools or jobs over the next several decades.