Updated

A study predicts that China's loosening of its one-child policy to allow all married couples to have two children will bring only a small increase in population growth.

The study, published Friday in the medical journal Lancet, recommends that China raise its retirement age to address an expected labor shortage.

It predicts that China's population of 1.37 billion will peak at 1.45 billion in 2029, compared with a peak of 1.4 billion in 2023 if the "one-child" policy had continued unchanged.

China brought in the policy in 1979 with the aim of limiting a surging population and promoting economic development. It was revised over the years to allow more couples to have an additional child, until the government allowed all married couples to have two children beginning this year.