Scotland's spring birth rate fell to its lowest level since records began, according to the most recent figures.
Provisional statistics show 12,253 births were registered in the second quarter of 2019 - 5.4% lower than 2018.
It is the lowest number recorded between April and June since registration began in 1855.
Scotland's population stands at 5.4m, the highest it has ever been, but the Scottish government said it faced "distinct challenges".
The National Records of Scotland also revealed there were 13,652 deaths in the same period - 0.2% more than last year.
The provisional figures for 1 April to 30 June 2019 showed that compared to the previous five years, births in the second quarter have fallen by 9.3% and deaths have risen by 0.9%.
This equated to a rate of nine births per 1,000 population, compared with 9.6 in the same quarter in 2018 and 11.4 a decade ago.
The report said possible reasons for the decline included women leaving motherhood until later in life, women having fewer children and economic uncertainty "particularly given that the beginning of the recent fall coincided with the financial crash a decade ago".
Fiona Hyslop, cabinet secretary for tourism, culture and external affairs, said: "Given our declining birth rate all of Scotland's population growth is predicted to come from migration. However, the UK government's proposals to end free movement of people and limit migration presents a real risk.
"We need to ensure we can grow our working age population to support our economy and society now and in the future when we expect more people to live longer beyond retirement."
Compared with the second quarter of 2018, there was an increase in deaths from dementia and Alzheimer's disease, and cancer. There was a drop in deaths from coronary heart disease and respiratory diseases.
The provisional figures also showed there were 7,613 marriages this spring - the lowest number recorded for that time of year.
There were 231 same-sex marriages, 20 fewer than in the same period last year, and 25 civil partnerships.
Paul Lowe, Registrar General for Scotland, said: "In line with recent trends, the number of births and marriages in Scotland continues to fall, with the numbers registered in the second quarter of 2019 being the lowest since civil registration began in 1855.
"The number of second quarter deaths was virtually unchanged from last year. However, it represents an increase of 6.9% since 2009, when the number of deaths reached their lowest ever level for quarter two."