Birth rates and fertility rates tend to decrease during economic downturns. This correlation is heavily supported by historical statistics, population surveys, and logical deduction. Given what a recession or depression means for expectations, it is understandable why many people would put off having more children. The United States has displayed this phenomena historically, including with the current downturn:
Dating back even further (to time periods from which I could not find continuous and reliable data), it has been noted time and time again that birth rates were especially low in the 30s due to the Great Depression. It is a pattern that we have also seen in other countries with both birth rates (reported as births per 1000 population) and fertility rates (births per woman).
Despite no longer being in an official recession, the recovery still has a way to go and general outlook on the economy is far from stellar. Preliminary data from 2010 and a study by the Pew Research Center suggest that birth rates continued to drop in the first year out of the recession. It would not be surprising to see further drops or stagnation in 2011 and into 2012 given the economic outlook through this time. The long-term implications could be substantial as the United States hovers around a fertility rate of 2, meaning a virtually stagnant population (minus migration). It could be another reason to reform policy to increase immigration.
On a side note, I apologize for not being able to find all the data (especially for the graph) from one source . If anyone has better data or supplemental research or articles to this post, I hope you share them in the comments.
Addendum: According to data from the World Bank, both crude birth rate and fertility rate went up slightly in the US in 2010. The crude birth rate is still below it’s pre-recession number (at 14 per 1,000 in 2010) and the fertility rate has bounced backed to 2.1. Of course, the exact figures before rounding could be slightly different too. Here is the data via Google: fertility rate and birth rate. Note that the past data does not exactly match up with the CDC either though, given different methodologies.