Scientists from Switzerland said countries with the toughest lockdowns in early 2020 and over-occupied intensive care units experienced the biggest drops in live births nine to 10 months later.
The team said these findings, published in the journal Human Reproduction, may lead to “long-term consequences on demographics particularly in western Europe where there are aging populations”.
Dr Leo Pomar, a midwife sonographer at Lausanne University Hospital and associate professor at the School of Health Sciences in Lausanne, Switzerland – and first author of the study, said: “The decline in births nine months after the start of the pandemic appears to be more common in countries where health systems were struggling and capacity in hospitals was exceeded.
“This led to lockdowns and social distancing measures to try to contain the pandemic.
“The longer the lockdowns the fewer pregnancies occurred in this period, even in countries not severely affected by the pandemic.
“We think that couples’ fears of a health and social crisis at the time of the first wave of Covid-19 contributed to the decrease in live births nine months later.”
England and Wales saw a 13% drop in live births in January 2021, compared to January 2018 and 2019 – while the number of babies born in Scotland decreased by 14%.
Lithuania and Romania saw the biggest drop in live births, at 28% and 23% respectively.
Sweden, which did not have a lockdown but did have a high number of deaths, did not experience a drop in live births, the researchers found.
The team found that the duration of lockdowns was the only factor associated with the decline in live births in January 2021, compared with January 2019 and January 2018.
Dr Pomar said: “The association we found with the duration of lockdowns may reflect a much more complex phenomenon, in that lockdowns are government decisions used as a last resort to contain a pandemic.
“Lockdown duration has a direct impact on couples.”
While live births have seen a rebound, March 2021 was the only month with a live birth rate similar to the pre-pandemic monthly rate, the researchers said.
But they added that this rebound does not seem to compensate for the decline in birth rates in January 2021.
Dr Pomar said: “The fact that the rebound in births does not seem to compensate for the decrease in January 2021 could have long-term consequences on demographics, particularly in western Europe where there are aging populations.”
Christian De Geyter, a professor at the University of Basel, Switzerland – who is the deputy editor of Human Reproduction, said the data on the impact of lockdowns on couples seeking fertility treatment is not available yet.
Prof De Geyter, who was not involved in the study, said: “These observations are important because they show that human reproductive behaviour, as evidenced by numbers of live births, changes during dramatic events, epidemics and global crises.”