This 'natality depression' reached its maximum levels about 6 months after the pandemic peak of the previous autumn.

“生育抑郁症”去秋季疫情高峰后大约6个月达到了最高水平。

He worked for NATO and studied natality.

他为北大西洋公约组织服务，研究出生率。

The dip in birth rates in spring of 1919 was followed by 'a compensatory natality increase in late autumn 1919 and early spring 1920, when natality significantly exceeded the expected rates.'

1919季出生率下降之后，“1919深秋和1920初的出生率出现了补偿性上升，当时的出生率明显超过了预期。”