A circular issued by the Ministry of Health, to take effect on March 10, said they would be rewarded with cash or gifts depending on where they live.

The other 20 localities are Can Tho City and 15 provinces in the south - Dong Thap, Hau Giang, Ba Ria-Vung Tau, Binh Duong, Long An, Bac Lieu, Tay Ninh, Soc Trang, Ca Mau, Dong Nai, Tien Giang, Vinh Long, An Giang, Ben Tre, and Kien Giang, and Da Nang City and Quang Ngai, Khanh Hoa and Binh Thuan in the central region.

The circular does not specify the value of the reward.

The fertility rate in the south has dropped sharply in recent years.

In 2019 the rate in HCMC had dropped from 1.76 children per woman of reproductive age to 1.39 compared to 2.75-2.38 in the central provinces of Ha Tinh and Nghe An.

In the southern provinces of Dong Thap, Hau Giang and Ba Ria-Vung Tau, the rates were 1.34, 1.53 and 1.37.

The national rate has been 2.09 for the last three years, lower than the globally agreed replacement fertility rate to sustain a population of 2.1.

Vietnam is among the most rapidly aging countries in the world. It entered the aging phase in 2011 when the number of people over 60 made up 10 percent of the population. That rate climbed to 12 last year out of a population of 95 million, and is expected to rise to 17.9 percent in 2025 and to more than 20 percent in 2038.

So it will take Vietnam just 30 years to transform from the aging phase to an aging country, compared to 115 years in France, 69 in the U.S. and 85 in Sweden.

A decision issued in April by Prime Minister Nguyen Xuan Phuc encourages people to marry before they are 30 and bear children early.

Women should have their second child before 35, it suggested.