In order to avoid a massive baby boom in the city between 2010 and 2012, the Shanghai Population and Family Planning Committee is planning to abolish a required waiting period for local couples allowed to have a second child under the country's one-child policy.

China's family planning laws limit most couples to having one child with violators of the law charged a "social-fostering fee" of about 50,000 yuan (US$6,024).

In certain cases, such as when both a husband and wife come from a single-child family, or when a couple's first-born has a non-hereditary handicap, a married couple is allowed to have a second child without penalty.

Currently, they must wait four years between births or face a monetary penalty, but officials want to abolish that requirement to lessen an expected baby boom.

The city has had two baby booms in its recent history, one around 1955 and the other during several years in the early 1980s with the peak coming in 1982, said Zhou Jianping, director of the city's family planning committee.

During those booms, maternity hospitals were overcrowded, leading to poor care for expectant mothers, said Zhou. Children born during those years also faced difficulty later in life getting into good schools and finding a job.

The boom in 1955 was caused by the government calling on married couples to have lots of children to help develop the country. That policy was changed in the early 1970s when China first adopted its family planning policy.

But when the baby-boomers from the mid-50s hit marrying age, another baby boom took place in the city.

At its peak in 1982, 220,000 babies were delivered in Shanghai. By comparison, the city has averaged about 90,000 births annually during recent years.

"According to our investigation and study, another baby boom is expected between 2010 and 2012." Zhou said.

By removing the mandatory four-year waiting period, many couples will be allowed to have their second child before that period, hopefully reducing the size of the baby boom and its effects on society, family planning officials said.