(KRON) — Researchers at the University of California, San Diego found what they termed “the Trump baby bump” in Republican counties after Donald Trump’s surprise victory in the 2016 Presidential Election.

The study found that Republican-leaning counties saw a sharp rise in birth rates, accounting to between 1-2% of the national birth rate in the two years after Trump’s win. Conversely, the researchers conversely found a baby slump in Democratic counties. The study was authored by Gordon Dahl, an economics professor, and William Mullins, a finance professor.

“The size of the change is equivalent to changes in birth rates that occur after economic shocks or in response to policies designed to affect birth rates,” Dahl stated in a UC San Diego press release. “For example, when unemployment drops by 1%, it increases national fertility by 1 to 2%, and when other countries provide a $1,000 subsidy to mothers for having a child, fertility rates rise by about 2%.”

The study is the first to establish a link between partisanship and birth rates vis a vis a presidential election.

When the study’s authors looked at birth rates of Hispanics versus non-Hispanics within counties, it found that Hispanic mothers had fewer births after the election — accounting for 2.3% of the national birth rate. “Hispanics were singled out by the Trump campaign and voted approximately two-to-one for Hillary Clinton in 2016,” the duo wrote.

Dahl and Mullins’ paper, which will be published in the American Economic Review, gives potential reasons for the difference in birth rates, including that by February 2017 Democrats’ and Republicans’ views on the economy flipped, with a strong majority of Republicans believing the economy was improving while most Democrats thought economic conditions were getting worse.

There were no fertility changes the authors were able to find that could be attributed to Barack Obama’s 2008 and 2012 wins; though they did find a similar effect in 2000, when George W. Bush won a close election after over a month when the results were contested.

“Our research really illustrates how polarized the country has become over the last 20 years,” Mullins stated in a press release. “Democrats and Republicans are deeply divided on their policy priorities and worries about the future, including on topics such as the environment, inequality, moral values and immigration. Polling data on voters’ satisfaction with ‘the way things are going in the U.S.’ reveals members of the two parties see the country through almost completely different lenses.”