It's a matter of personal choice. I wouldn't advise it because if you were to get pregnant, you wouldn't know for at least the first two weeks. During that time you could have an accident or the strain could cause miscarriage.
Roller Derby - brand - was created in 1936.
Roller Derby Germany was created in 2011.
Helsinki Roller Derby was created in 2009.
Houston Roller Derby was created in 2005.
Pacific Roller Derby was created in 2008.
Junior roller derby was created in 2007.
Roller Derby Toulouse was created in 2010.
Wasatch Roller Derby was created in 2008.
NEO Roller Derby was created in 2007.
Toronto Roller Derby was created in 2006.
Maine Roller Derby was created in 2006.
Stockholm Roller Derby was created in 2007.