A spokesperson from China's top health authority said that fluctuations in the country's population are being closely monitored and the 2018 birth figures will soon be released, Chinanews.com reported on Jan. 10.

Some population experts have predicted that the number of births in China will fall by two million this year compared with 2018.

Song Shuli, a spokesperson for the National Health Commission, said multiple factors affect birth rates in China, including the number of women of childbearing age, the average age of women getting married and giving birth, and social and economic factors.

Tao Tao, a population researcher with the Renmin University of China, explained that one major reason for the slump in births is a decreasing number of women of childbearing age.

Statistics indicate that in 2015, more than half of all women of childbearing age were over 40 years old. Tao noted that the number of women between 15 and 49 in China peaked in 2011, and has been falling ever since.

Another reason for the drop in population figures is that the average age of women bearing their first and second children have both increased by a year over the past three years. This may be partially caused by the fact that people are getting married later, meaning they are also having children later in life. In 2017, the number of couples getting married dropped by 7 percent year-on-year to 10.63 million.