The baby boom that many Americans predicted would result from couples being isolated together during the coronavirus pandemic has not panned out so far.

Instead, the opposite occurred in 2020, with more than 50,000 fewer births in several U.S. states compared with a year earlier, according to a survey conducted by the Guttmacher Institute.

Birth rates in Arizona, California, Florida, Hawaii and Ohio saw significant declines in the nine months after COVID-19 was declared a national emergency, Bloomberg News reported.

The overall U.S. birth picture could change as more states report data.

So far, though, the data affirms what the study indicated from the start of the pandemic, when more than 40% of women reported they changed their plans about when to have children or how many children to have due to COVID-19. One-third of the women surveyed said they wanted to delay pregnancy or have fewer children because of the pandemic.

A separate study by the public policy nonprofit Brookings predicted 300,000 and 500,000 fewer births in 2021 as a result of the pandemic.

The Guttmacher study took particular note of December births in California, which dropped by 19% year over year in the highest populated state in the country. The same data showed the state added only 21,200 new residents through July 1, the slowest rate of growth since 1900.

“These are, to put it mildly, very large declines in historical terms,” said Philip Cohen, a sociologist at the University of Maryland, regarding the California drop. “One thing we don’t yet know is how much of this is driven by people moving around, rather than just changes in birth rates.”