To estimate the number of women pregnant at any time in China, they have
Firstly, they have solved for the % of women pregnant any time and arrived at (2%)
Secondly, they have assumed that 50% of China's population as women.
Thirdly, they have directly multiplied 2% with the total women count in China.
Shouldn't we segment the women population again into age-groups before the aforementioned 3rd step to get a realistic number of pregnant women in China?